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 Frontispiece
 Title Page
 Letter of transmittal
 Foreword
 Acknowledgement
 Table of Contents
 List of Illustrations
 Dunes
 East coast barrier-islands and...
 East coast dunes
 Northwest Gulf coast dunes
 Dune patterns as determined by...
 Dune migration
 Soil reactions
 Recognition of plants
 Cacti
 Lichens
 Mosses
 Scrub
 Final word
 Literature cited
 Index














Florida dunes and scrub, vegetation and geology ( FGS: Bulletin 23 )
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Title: Florida dunes and scrub, vegetation and geology ( FGS: Bulletin 23 )
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Table of Contents
    Frontispiece
        Page 1
        Page 2
    Title Page
        Page 3
        Page 4
    Letter of transmittal
        Page 5
        Page 6
    Foreword
        Page 7
        Page 8
        Page 9
    Acknowledgement
        Page 10
    Table of Contents
        Page 11
    List of Illustrations
        Page 12
        Page 13
        Page 14
    Dunes
        Page 15
        Page 16
    East coast barrier-islands and lagoons
        Page 17
        Page 18
        Page 19
    East coast dunes
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
        Page 48
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
        Page 54
        Page 55
        Page 56
        Page 57
        Page 58
        Page 59
        Page 60
        Page 61
        Page 62
        Page 63
        Page 64
        Page 65
        Page 66
        Page 67
        Page 68
        Page 69
        Page 70
        Page 71
        Page 72
        Page 73
        Page 74
        Page 75
        Page 76
    Northwest Gulf coast dunes
        Page 77
        Page 78
        Page 79
        Page 80
        Page 81
        Page 82
        Page 83
        Page 84
        Page 85
        Page 86
        Page 87
        Page 88
        Page 89
        Page 90
        Page 91
    Dune patterns as determined by plants
        Page 92
        Page 93
        Page 94
        Page 95
        Page 96
        Page 97
        Page 98
        Page 99
    Dune migration
        Page 100
    Soil reactions
        Page 101
        Page 102
        Page 103
    Recognition of plants
        Page 104
        Page 105
        Page 106
        Page 107
        Page 108
        Page 109
        Page 110
        Page 111
        Page 112
        Page 113
        Page 114
        Page 115
    Cacti
        Page 116
    Lichens
        Page 117
        Page 118
        Page 119
    Mosses
        Page 120
    Scrub
        Page 121
        Page 122
        Page 123
        Page 124
        Page 125
        Page 126
        Page 127
        Page 128
        Page 129
        Page 130
        Page 131
        Page 132
        Page 133
        Page 134
        Page 135
        Page 136
        Page 137
        Page 138
        Page 139
        Page 140
        Page 141
        Page 142
        Page 143
        Page 144
    Final word
        Page 145
    Literature cited
        Page 146
        Page 147
        Page 148
    Index
        Page 149
        Page 150
        Page 151
        Page 152
        Page 153
        Page 154
Full Text
Panama City Beach Blow-out. Saw palmetto remnant of turret-dune encircled by a trough scoured by eddying
currents. Oak skeleton shown, right rear.




STATE OF FLORIDA DEPARTMENT OF CONSERVATION
Florida Geological Survey S. E. RICE, SUPERVISOR OF CONSERVATION Herman Gunter, Director, Geological Survey
GEOLOGICAL BULLETIN NO. 23
FLORIDA DUNES AND SCRUB, VEGETATION AND GEOLOGY
By
HERMAN KURZ, Ph. D. FLORIDA STATE COLLEGE FOR WOMEN
Tallahassee
Published for THE STATE GEOLOGICAL SURVEY Tallahassee, 1942


Published December 15,1942
The e. o. Painter printing co.t
delano, fla.


LETTER OF TRANSMITTAL
Honorable S. E. Rice, Supervisor Florida State Board of Conservation
Sir:
It is a pleasure to transmit Geological Bulletin No. 23 of the Florida Conservation Department, entitled, "Florida Dunes and Scrub, Vegetation and Geology" by Herman Kurz, Ph. D., Professor of Botany, Florida State College for Women, Tallahassee.
This bulletin embraces an intriguing subject, for our coastal dunes have long been one of our significant attractions. Dr. Kurz has correlated our present dunes and those lying inland, or fossil, with the scrub in such a fascinating manner as to make this study of interest not only to the scientist but likewise to the layman. It has been his purpose to present the story of the dunes and scrub in a scientifically accurate manner, yet so written as to have popular appeal. In this he has delightfully succeeded and the report will as a result be all the more welcomed by our own citizens and will prove popular with our many visitors and non-residents.
This paper has been prepared by Dr. Kurz almost without expense to the Florida Geological Survey other than preparing some of the illustrations and the cost of printing. This generous cooperation is much appreciated and herewith acknowledged.
Very respectfully,
Herman Gunter, Director Florida Geological Survey
Tallahassee, Florida September 10, 1942




FOREWORD
Diminishing to ever smaller areas is Florida's seaside scenery. Mutilated or gone, and still going, is much of the picturesque coastal topography. Yet, this vanishing natural beauty of the coast has helped to bring many people to Florida: nature lovers have come to enjoy, scientists to study the phenomena and beauty of the sand dunes fringing the coasts of the State. Seeking relaxation, visitors have come a long way to walk the beaches, to ride the sand, or to hunt rare shells. Some come just to see the ocean, turn around to play in the sand, then consider the dune behind as a setting for a permanent seaside home. Naturally enough the most attractive areas are the first to go as sites for summer homes or as grounds for public recreation. In the interest of enterprise linked up with bathing beaches expansive areas of striking sand dunes and vegetation are rendered into monotonous plains of barren sand. It would not be sensible to discourage the use of one of the State's most valuable resourcesfacilities for play and recreation at the seacoast.
Perfectly applicable to beaches and dunes is the following statement of a former governor's commission: "It is the responsibility of the State to make its outstanding scenic, botanical, historical, and recreational areas available, accessible and useable for this purpose."1 But it is obviously not prudent to permit indiscriminate obliteration of the very landscape features along the ocean or gulf that attract so many people.
Ages are involved in the development of a dune landscape entailing a complete sequence of dune ridges and vegetation from the sea-oats at the beach to the live oak, magnolia, and palms of the hammock in the rear. A few days suffice for man to destroy the product of centuries, but only time, reckoned in hundreds of years, can reproduce a complete natural landscape of dunes. Samples of primitive seaside dunes and vegetation "unimproved" by man would afford variety for travelers, out-
i Report of the Governor's Commission on the Conservation of Florida's Natural Resources, March 25, 1937, p. 10,


door laboratories for naturalists, and havens of solitude for others. Turning again to the commission report we read:
"It has been estimated that the tourists bring into Florida $200,000,000 each year. These people are searching for the scenes they have read about describing the wonderlands of our State. An infinitesimal fraction of this income was reinvested to provide such areas until the Florida Board of Forestry was authorized to acquire, establish, and maintain a system of State parks. A well-established, maintained, and advertised system of State parks where bathing, boating, fishing, hunting, picnicking, and camping can be enjoyed will attract more tourists and increase the revenue of the State." 2
While there is yet a choice of selection, large coastal parks should be established in order to preserve as samples for all time some of the very kind of primeval beauty and things of nature that have helped to make Florida. Not all of the most fascinating coastal scenery should go into seaside cottages, obliteration, or artificiality.
In studying the relationship of geology and vegetation of dunes and scrub I have taken a method of attack and presentation hitherto not applied to Florida. To anyone observing a series of seaside dunes on a breezy day the dynamics of waves, wind, and sand is soon apparent: There is a bringing up of debris by the surf, a chasing in of dried beach sand by air currents. Here a sand hill is growing and plants are anchoring it; elsewhere a mound is undermined and plants are dying for loss of foothold. Building or tearing down the earth's external features is a physiographic process. A consideration of the rock substratum takes us into structural geology. Some sands are rich or poor in lime according to the shell contents of underlying rocks that yield the sand to waves and wind. The soil resulting from the rock, according to its particular properties affects the nature of the plant growth. And there it is: lifting wave, carrying wind, piling sand, the kind of sand, the kind of rock, the kind of plantsphysiography, geology, plants, all correlated.
From foredune to quiescent hinterland hammock there is every degree of change; geological structure fundamental to the supply of sand is also a thing of change. With modification of topography and of substratum come differences in vegetation. Seacoast topography and vegetation are not static; they are dynamic. And that is the point of view.
2 Ibid.


With the embodiment of considerable new material, point of view, and conclusions, I have hoped to strike the interest of students in botany and geology. But by cutting technical terminology to a minimum I have also striven to enlist the layman as a reader. I can only wish that professional and layman alike will each forbear the compromise made in order to enlist the interest of both..
The photography and figures were designed to help students of nature and'teachers to recognize the commoner plants by location and by line drawing. Even trained botanists coming to Florida from a different flora find it tedious, if not difficult, to try to determine the name of a plant with a cumbersome key. Because of the ubiquity of the woody plants, their leaf characters are emphasized in the delineations.
A special plea for the conservation of scrubs seems superfluous. Remoteness from and disrelation to salt water surf as well as undesirability for cultivation constitutes ample protection. However, because of certain well defined affinities to dunes, the Florida scrub was incorporated as an important part of this publication.
Very seldom is a traveler or resident of the State more than fifty miles from some intriguing sand dunes or mysterious scrub. If with this work I have given something to students of botany and geology; if I have helped teachers of Florida to call by name and see the relations of just a few plants often nearby; or if I have made more friends for dunes, plants, and conservation, I shall feel gratified.
H. K. 1942
Florida State College for Women Tallahassee, Florida.
l-A


ACKNOWLEDGEMENTS
I am indebted to Herman Gunter, Director, Florida Geological Survey, for professional advice and suggestions on the geological aspects, for participation in the field, and for general suggestions during the progress of the work. To Sidney A. Stubbs, Associate Geologist, Florida Geological Survey, I am also indebted for advice on geology and soils, and for aid in the field. Recognition is due to William Dean Wilson, Draftsman, Florida Geological Survey, for the delineation of the profile plates and line drawings of the plants, unless otherwise noted.
Thanks are due to Erdman West, Director of the Herbarium, Agricultural Experiment Station, University of Florida, who made determinations of many difficult and doubtful specimens of seed plants. To Dr. Ruth O. Schornherst, Department of Botany and Bacteriology, Florida State College for Women, goes credit for identification of the mosses; I gratefully acknowledge the service of Mrs. Joyce H. Jones, Museum Herbarium, University of Michigan, for determination of the lichens. For identification of the cacti I am indebted to Dr. Elzada U. Clover, Department of Botany, University of Michigan.
I wish also to acknowledge the counsel and cooperation of Dr. R. V. Allison, Director of the Department of Soils, University of Florida Agricultural Experiment Station, and to extend credit to J. R. Henderson, Soils Technologist of the same department, for advice pertaining to procedure on the soil problems, nomenclature of soils and participation in the field.
A number of students working in or for the Department of Botany and Bacteriology have given assistance: Amanda Zewadski, in photography; Margaret Hart and Jo Anne Potts, in the preparation and records of the herbarium specimens; and Elizabeth Baggs, in field observations. Lois Steinhoff, a student of the Florida State College for Women, contributed her time and skill in the exploratory work connected with the drawings of some of the plant specimens.
Throughout the prosecution of this work, Myrtis T. Kurz, my wife, has been a source of encouragement, has given aid in the field, and in the preparation of the manuscript.


Page
Foreword .............................................................................................................. 7
Acknowledgements ............................................................................................ 10
Dunes .................................................................................................................... 15
East Coast Barrier-Islands and Lagoons .................................................... 17
East Coast Dunes............................................................................................ 20
Cape Canaveral ........................................................................................ 20
Physiographic Development ............................................................ 20
Dune-building Plants ...................................................................... 22
Dune Succession .............................................................................. 26
Species on Sterile and Fertile Sands............................................ 28
Plant List ............................................................................................ 29
Jupiter Island ............................................................................................ 31
Two Vegetation Types .................................................................... 31
Geological History ............................................................................ 38
Plant List ............................................................................................ 39
Crescent Beach .......................................................................................... 40
Formation of Dunes .......................................................................... 40
Dune Erosion ...................................................................................... 44
Blow-outs ............................................................................................ 47
Stream-lined Vegetation ................................................................ 48
Plant List ............................................................................................ 50
Daytona Beach .......................................................................................... 51
Shoreline Features ............................................................................ 52
Succession ............................................................................................ 52
Plant List ............................................................................................ 54
Vilano Beach.............................................................................................. 56
Blow-outs ............................................................................................ 56
Retrogression ...................................................................................... 56
Succession........................................................................................... 57
Plant List ............................................................................................ 59
Ponte Vedra ................................................................................................ 61
Saw-palmetto and Cabbage-palm ................................................ 61
Blow-outs ............................................................................................ 66
Plant List ............................................................................................ 72
St. Johns Bluff.......................................................................................... 73
Scrub and Climax Forest ................................................................ 74
Plant List ............................................................................................ 75
Northwest Gulf Coast Dunes ........................................................................ 77
Cochran's Beach ........................................................................................ 77

Shore Erosion .................................................................................... 78
Plant List ............................................................................................ 82
Climax Forests of Lamark and Carrabelle.......................................... 82
Beacon Hill.................................................................................................. 85
Flatwoods Swale ................................................................................ 87
Establishment of Oaks................................................................... 90
Hardwood Climax ............................................................................ 90
Plant List............................................................................................ 91
Dune Patterns as Determined by Plants.................................................... 92
Dune Migration ...........................................,...................................................... 100
Soil Reactions ..........................,......................................................................... 101
Recognition of Plants ...................................................................................... 104
Plates of Plants and Descriptions ....................................................106-115


Page
Cacti ...................................................................................................................... 116
Lichens ................................................................................................................ 117
Lichens and Lichen Localities .............................................................. 118
Mosses .................................................................................................................. 120
Mosses and Localities .............................................................................. 120
Scrub .................................................................................................................... 121
Scrub and High Pine Land...................................................................... 123
Water and Chemical Relations .............................................................. 128
Geological Aspects of the Scrub .......................................................... 136 \y
Lateral Expansion of Scrub .................................................................. 139
Succession in Scrub .................................................................................. 141S
Physiographic Scrub Climaxes .............................................................. 143 \,
Final Word ........................................................................................................ 145
Literature Cited ................................................................................................ 146
Index .................................................................................................................... 149
ILLUSTRATIONS
Plate Plates Page
Panama City Beach Blow-out ..............................................Frontispiece
1 Dune types related to different plant growth forms .................... 25
2 Cape Canaveral dune ridges and vegetation ................................ 27
3 Cape Canaveral profile ........................................................................ 30
4 Jupiter profile........................................................................................ 32
5 East Coast dunes of Jupiter and Crescent Beach ........................ 35
6 Crescent Beach profile ........................................................................ 41
7 Stream-lining on the seacoast .......................................................... 49
8 Daytona Beach profile ........................................................................ 55
9 Three scrub types, east coast and interior .................................... 58
10 Vilano Beach profile.............................................................................. 60
11 Ponte Vedra profile .............................................................................. 71
12 St. Johns Bluff profile .......................................................................... 76
13 Cochran's Beach profile ...................................................................... 83
14 Northwest gulf coast dunes .............................................................. 86
15a Beacon Hill profile................................................................................ 88
15b Beacon Hill profile continuation ........................................................ 89
16 Dune types and associated plants on northwest gulf coast........ 93
17 Northwest gulf coast dune scenes .................................................... 99
18-22 Line drawings of plants ..................................................................107-115
23 Scenes to show scrub and high pine land........................................ 125
24 Profile drawings to show influence of elevation and soil water
on species content of scrub ................................................................ 131
Figure Figures Page
1 Outline map of Florida showing location of beaches.................... 17
2 Profile across Indian River and offshore bar near Eau Gallie, Brevard County .................................................................................... 19
3 Airplane view of Daytona Beach on offshore bar ........................ 20
4 Blowing Rocks, iyz miles north of Jupiter Light........................ 33
5 Dunelets elongated parallel with wind direction. Santa Rosa Island, near Camp Walton ................................................................ 40
6 Wave-cut sand scarp south of Ponte Vedra .................................. 46
7 Shoreline encroachment, foredunes, and blow-outs near Ponte Vedra, St. Johns County...................................................................... 62
8 Stages to show how a cabbage-palm stem anchors plant.......... 63


Figure Figures Page
9 Ascending saw-palmetto in Ponte Vedra hammock .................... 64
10 Cabbage-palms in shallow lagoon south of Ponte Vedra, St. Johns County .......................................................................................... 65
11 Blow-out dune invading cabbage-palms. Jacksonville Beach, Duval County ..........................................................,............................. 66
12 Shore encroachment killing and undermining cabbage-palms .... 68
13 Ponte Vedra dune hammock with magnolia in lee of blow-out. 69
14 View from ancient dunes at St. Johns Bluff, Duval County ...... 73
15 Eroding shore of St. George Sound two miles east of Apalachi-cola Bay bridge .................................................................................... 79
16 Shore of Inlet Lake, near boundary of Bay and Walton Counties 80
17 Pine tree stump and top roots protruding through beach sand 81
18 Magnolia climax at Lanark, Franklin County ............................ 84
19 Sea-oat and saw-palmetto dunes at Indian Pass ........................ 95
20 Low young sea-oats dune ridge west of Panama City Beach .... 96
21 High old blow-out ridge with sea-oats .......................................... 96
22 The effect of dune burial and migration on slash-pine................ 101
23 Scrub vegetation on white sand on east side of Lake Kingsley, Clay County ............................................................................................ 122
24 Profile view of pit in scrub, Orlovista, Orange County .............. 134
Table Tables Page
1 Selected chemical soil data ................................................................ 34
2 Some factors operative in dune altitude ........................................ 43
3 Sand resistant depth in scrub and high pine land ........................ 135




FLORIDA DUNES AND SCRUB, VEGETATION
AND GEOLOGY
Herman Kurz
DUNES
"That most mysterious constellation, the Southern Cross, smouldered and winked over the dunes; the chant of the surf sounded like deep basses intoning an elegy for a world beautiful but forgotten ages ago"
Anthony Adverse.*
Beaches of Florida are smooth. The sand makes them so. Gentle mounds or sloping dunes provide mild variety. And farther back lies a landscape of restful green. It seems to have been always. Very few wonder what sequences, what wear and tear of the ages were necessary to bring about such "beautiful simplicity." As Shaler expresses it in Sea and Land:
"In fact, these even shores present a greater array of actions, and afford the student a larger field of profitable inquiry, than he has found in the apparently more varied rock coast. It is because all the conditions of the geologic life which lead to their growth and maintenance are perfectly adjusted to each other, that the well-organized beaches appear so simple." 3
Hardly anyone realizes what an immense span of time will be required to restore a complete seaside landscape once the native vegetation has been scorched and once the sand hills have been scraped down to an ugly waste of sand.
The eastern coastline of Florida appearing at first so simple will with sustained attention reveal a number of aspects which incite curiosity. That the newer mounds or ridges of sand nearest the beach are the work of winds is obvious; that the larger ones farther back are but the older handiwork of similar winds of long ago is also plain enough. The necessity of prevailing onshore winds is soon apparent. And it does not take long to realize that the waves wash up the sand leaving it high where it may dry for subsequent removal by driving air cur-
*From Anthony Adverse (p. 630), copyright 1933 by Hervey Allen, and reprinted by permission of Farrar and Rhinehart, Inc., Publishers, New York.
3 From Sea-Beaches: Sea and Land (p. 41), copyright 1894 by N. S. Shaler, and reprinted by permission of Charles Scribner's Sons, Publishers, New York.


i Martens, James H. C, Beaches of Florida: Florida Geol. Survey, 21st-22nd Ann. Rept., pp. 19-119, 1931.
5 Cooke, C. Wythe, Scenery of Florida, interpreted by a geologist: Florida Geol. Survey Bull. 17, pp. 61-79, 1939.
6 Cressy, George Babcock, Dune accumulation: The Indiana sand dunes and shore lines of the Lake Michigan basin (1929), pp. 35-50.
" Shaler, N. S., op. cit., pp. 38-74.
s Cornish, Vaughan, On the formation of sand-dunes: Geographical Jour., vol. 9, pp. 278-299, 1897.
rents. But the source from which the sand is replenished to the shore bottom as fast as waves deposit it on the beach might cause some speculation. Then there are the even-crested sand ridges paralleling each other and the shore; one, often at or near the ocean front, is nearly always definitely the larger "master ridge." What accounts for this prominent ridge? Why is it sometimes fronted with a vanguard of smaller subordinate ridges and sometimes without them? In the greater part of Florida's coastal dunes this one large ridge is there. Did that just happen? Or is it related to some other coastal process? Even the fact that the ridges, although parallel to the coast line, are nevertheless transverse to wind direction calls for explanation. Sometimes, on the contrary, dunes are elongated parallel with the path of winds. Again, how do we explain the uniform height and evenness of the crests of the ridges? All of these features and others besides are tied up with conditions and processes prevailing at the coasts of Florida. For a general background and picture of Florida sand dunes the reader will do well to consult a work by Martens4 and one by Cooke.5 For a thorough account of the physical processes of dune development Cressy6 is recommended. Shaler's study7 on beaches and dunes is simply written and fascinating.
Desert dunes are notably different from coastal ones. Cornish8 has provided the basic facts discussed in this paragraph. According to him, relative abundance of sand load, density and size of sand grains, velocity and direction of wind, scarcity or absence of plants and water are all important factors. With plants out of the picture, the physical conditions of substratum, sand, and air practically determine the character of dunes in the desert. Variation is in accordance with the nature or whim of one or more factors; but usually the windward side is a gentle slope and the leeward side a steep one whose angle of slope is determined by the angle of rest for the sand and the eddying influence of wind curling over, behind, and


around the dune. Strong winds and limited sand supply produce elongated dunes while weaker winds form long dune ridges transverse to the path of the wind. Still other dunes are of the crescentic or horseshoe types with the arc facing the wind. A technical discussion of these is here not warranted. The significant point is that Florida's coastal dunes because of different conditions are in important respects unlike desert dunes. Desert dune building concerns only physical properties
EXPLANATION
CAPE CANAVERAL JUPITER ISLAND CRESCENT BEACH DAYTONA BEACH VILANO BEACH PONTE VEDRA ST. JOHNS BLUFF
8 COCHRANS BEACH
9 BEACON HILL
2 3 4 5 6 7
SCALE
40 60
MILES
Figure 1.Outline map of Florida showing location of beaches.
and processes; plants are unimportant; coastal dune construction also a physical process involves not only substratum, sand, and wind, but also anchoring plants, and the waves or currents of coastal waters.
EAST COAST BARRIER-ISLANDS AND LAGOONS
It now seems desirable to consider still another aspect fundamental to our main studies.
Any map of Florida will reveal that most of the east coast of Florida is flanked by a long narrow strip of land running parallel to the mainland. Since most of Florida's east coast recent dunes facing the ocean front are on these islands or peninsulas, a brief discussion, at least of their origin, seems justifiable. The complicated and in part controversial develop-


ment of offshore bars makes it inadvisable to attempt a detailed treatment. Anyone wishing a critical analysis should read Johnson.9 But the writer will hazard a condensed and elementary explanation based on Cooke,10 Shaler,11 Martens.12 It appears established that most of the sand going into the construction of the east coast barrier-islands originates from the Piedmont or southeastern Appalachians via ancient or modern rivers emptying into the ocean; via prevailing shore currents or beach drifting13 of geologic and recent times slowly relaying the sand southward to Florida coastal waters. About offshore bar development Martens writes:
\ "'An offshore bar or barrier beach is a narrow bar with its surface only slightly above sea level, lying parallel to and some distance out from, a gently sloping sandy shore. Between the mainland and the bar lies a lagoon, which in some parts of Florida is, called a 'river' and in some parts a 'sound' or a 'lake,' as for example Indian River, St. George's Sound, and Lake Worth. Because of the shallow depth of the lagoon and the comparatively short reach which the wind has, there are only small waves to strike against the mainland shore and the inner shore of the offshore bar. The real beach is on the outer side of the offshore bar. The offshore bar is formed by waves breaking in shallow water [breaker zone], washing up sand from the bottom and piling it up closer to shore until finally it rises above the surface of the water. Most of the Atlantic and Gulf beach in Florida is on offshore bars, some of which are real islands separated from the mainland by open water, others islands separated from the mainland only by marshes and narrow tidal creeks, and still others peninsulas connected at one end with dry landV) Figures 2' and 3 show the
generaL^relatlbns of the offshore bars, lagoons and-mamlandr-. .
o Johnson, D. W., Shore processes and shoreline development (1919), pp. 348-394.
" Cooke, C. Wythe, op. cit., p. 60.
n Shaler, N. S., Sea and land, p. 47.
Martens, James H. C, Beaches of Florida, pp. 79-80.
i3~TOarteTVs; James H. C, Beach sands between Charleston, South Carolina, and Miami, Florida: Bull, of the Geol. Soc. of America, vol. 46, p. 1590, 1935.
14 Martens, James H. C, Beaches of Florida, pp. 90-91.


The writer might add that the real contention is whether barrier-islands are formed entirely by materials derived from local erosion of the sea bottom by onshore wave action, or whether the shifting of longshore currents supplies most of the material necessary for the building. Johnson 15 concludes that in the early stages deposition of locally eroded material is mostly responsible; for the later stages of the bar he states that longshore currents play an important role.
Figure 2.Profile across Indian River and offshore bar near Eau Gallie, Brevard County. From Martens, Beaches of Florida.
The barrier-islands of Florida are further complicated16 by the fact that underlying them is a foundational rock of coquina or calcareous sandstone upon which the offshore bars have been superimposed. But two facts still remain: (1) most of the sand on top of the barriers either as beach or dune has in geological times come from farther north, for as Cooke17 argues the surface rocks of the mainland contain very little sand; (2) shore currents are today shifting sands southward which replenish what beaches yield to the dunes.
1 s Johnson, D. W., op. cit, p. 392.
i6 Cooke, C. Wythe, Scenery of Florida, p. 65; Martens, James H. C, Beaches of Florida, pp. 90-91; Johnson, D. W., op. cit., p. 373. it Cooke, C. Wythe, Scenery of Florida, p. 60.


east coast dunes
CAPE CANAVERAL
Physiographic Development
Cape Canaveral with its system of lagoons, inlets, peninsulas, islands, slender bars, and foreland terminating in a triangular point presents a configuration on the map that challenges interest. An instructive example of different types of processes
Figure 3.Airplane view of Daytona Beach on offshore bar, Volusia County. From Martens, Beaches of Florida. (Photo by r. h. LeSesne.)


operative in shoreline development, this cape receives considerable attention in Johnson's thorough book Shore Processes and Shoreline Development. Ordinarily offshore bars are subjected to inlandward driving by the very forces that created them as soon as they are initiated; that is, as physiographic features offshore bars are transient. In the normal processes wind and waves attacking the sand at the front, as it were, roll the bars inlandward, slowly but inexorably forcing them to cross the lagoon behind and to join the mainland. Cape Canaveral, however, is classified as a prograding type of barrier-islandone that is actually building the shore into the water.18
In the geological past this offshore bar has advanced on both the northeastern and southeastern fronts. At a later time there was, and still is, erosion (retrogradation) on the northeastern face; shore currents have carried and still are carrying this debris around the triangular point to the southeastern side. Here waves and wind have deposited and still are depositing a parallel series of beach and dune ridges ranging from young embryonic types to old quiescent ones. Successive periods of advancement and retreat of the shore have produced at one site a system of characteristically parallel dune ridges and at another a parallel series with typically truncated ends. The final product as it stands today at Cape Canaveral is according to Johnson a complex cuspate foreland.19
Complicated by its physiographic past and by its underlying coquina rock, rich in ancient shells, Cape Canaveral has nevertheless recorded a story of dune-vegetational development that is relatively easy to follow. Here dunes are in the building from the smallest incipient ones near the beach to those which for ages have lain quiescent far in the background. The advancing shore is adding successively ridge after ridge. Upon these basic beach ridges the winds are superposing sand dunes with perfect blending and coincidence. Keeping step with the dune progression is a perfectly timed vegetation whose species supercede one another from the newest foredunes to the most ancient ones in the rear according to seniority of sand and hill. The shore south of the lighthouse affords a magnificent example of prograding and ridge building. This is the site chosen for study.
is Johnson, D. W., op. cit., pp. 319, 380, and 382. io Ibid., p. 325.


Dune Building Plants
The first ridge at Cape Canaveral, entirely wave formed, is practically devoid of plants. Here mechanical action prevents establishment of any kind of plant. For the same reason the trough behind it is clean of growth. Even in the somewhat sheltered troughs farther back pioneer species like railroad-vine,20 Ipomoea stolonifera (a morning-glory), camphor-plant, and seaside evening-primrose are killed by high storm tides. Others also in the low placesmarsh-elder, Scaevola Plumieri, (no common name) rush-grass, creeping-spurge #seem more tolerant of salinity and immune to mechanical action. The second ridge displays a narrow line of low-perched dunelets anchored by plants. Prominent as dune binders are the sea-oats, marsh-elder, Scaevola Plumieri, beach-grass, rush-grass, and beach-orach. By infiltration, as it were, seeds lodge behind an obstacle, shell, or similar object or in a scoured hole where they germinate. By their very presence they now offer increased obstruction to aeolian sand. From this time on, plants and dunes, reciprocally dependent, grow with equal pace. Years ago Cowles21 wrote that duration of dunes coincides with the life of the plants anchoring them. Following his reasonable lead, we will see that dunes anchored solely by annuals like beach-orach, sea-rocket, or saltwort are of short durationa year or less. With the death and disintegration of the annual plant comes the end of the dune unless it is taken over by a longer-lived species. A biennial like seaside evening-primrose
soErdman West, Director of the Herbarium, Agricultural Experiment Station, University of Florida, determined or checked all species of doubt; but I assume the responsibility of any possible errors in nomenclature. For the thoroughness of Mr. West, I am grateful.
Roland M. Harper's several works on the vegetation and geography of Florida have been of great assistance in locating and identifying species in the field. See titles cited.
In an attempt to make this work serviceable to a maximum number of readers the running text will use common names wherever possible according to the usage of Small's manual. The tabulated lists will give scientific names for those interested in technical nomenclature. For the sake of consistence, scientific and common names of all seed plants are, unless otherwise noted in the context after John Kunkel Small's Manual of the Southeastern Flora (1933).
*In a few species (marked *) the use of common names follows: Penfound, Wm. T., and O'Neill, M. E., the vegetation of Cat Island, Mississippi: Ecology, vol. 15, No. 1, passim, 1934.
si Cowles, Henry Chandler, The ecological relations of the vegetation on the sand dunes of Lake Michigan, Bot. Gaz., vol. 27, pp. 174-175, 1899.


can, because of its densely branched straggling stem system, build a low mound of several square feet. But the dunes depending on it are necessarily limited to two years. An annual like the creeping-spurge, is, because of its tininess, and stems and leaves flat against the sand, unimportant even as a temporary dune builder. Dunes, then, held by annuals and biennials are very fleeting. It must be clear that for continued building, which will result in large dunes of many years, longevity of plant is prerequisite. Woody plants live long enough; but they are not able even to start on shifting sands of a raw beach dune. The best initiators of a dune or dune system are the perennial herbs. Naturally enough within this class are species of varying degrees of efficiency and peculiarities. Sea-purslane, for example, starts in low wet areas where it may form dunes of considerable expansion, but with a height ordinarily limited to a few feet. There is little upward or downward development on the part of its loosely branched and tender substratum stems and roots. Because of shallow lateral growth of rhizomes and the high water content of the sand holding the plant, sea-purslane dunes tend to be smooth and flat or convex in contour.
The runners of the railroad-vine radiating from a parent stock skim the surface of sand up to twenty-five feet away. Lacking a closely interlaced system of buried stems, the railroad-vine is not well equipped for consolidation. It can, however, because of speedy growth keep above sand that does not pile too rapidly and sometimes can sneak up the slope of a dune more or less stabilized by other plants. In opposite extreme to the railroad-vine stands the sand-rush. This species grows in isolated clumps a foot or two high. It propagates by means of a densely packed vertical underground stem system, but makes negligible lateral gains; moreover its high water requirement keeps it from rising much above the wet sand. In short, isolation, high water requirement, and inability to spread make this type of perennial of little import in building dunes.
Cowles 22 has specified the requirements of a successful dune-former as follows: the plant must be perennial with the ability to spread laterally and at the same time to keep above the sand; at times the plant must be able to endure extremely dry conditions, the roots extreme exposure or the stem burial. "In
22 Ibid., p. 182.


Oosting, Henry J., and Billings, W. D., Factors affecting vegetational zonation on coastal dunes: Ecology, vol. 23, no. 2, pp. 137-139, 1942.
EXPLANATION OF PLATE 1
Dune types related to different plant growth forms. Top: Elongated and precariously held railroad-vine dunes; Indian Pass, Gulf County. Middle: Turret dune of saw-palmetto formed by scouring wind and slumping of sand in blow-out; Panama City Beach. Bottom left: Biscuit dune of twin live-oak due to scouring winds' inability to remove sand captured and held by intricate mass of stems and roots; Panama City Beach. Bottom right: Mole-hill dunelets formed by clumps of sand-rush Fimbristylis castanea which are incapable of making an appreciable lateral growth and are not able to elevate the dune much above a wet substratum; Indian Pass, Gulf County.
short, a successful dune-former must be able at any moment to adapt its stem to a root environment or its root to a stem environment."
The sea-oat is the one dune plant of Florida that meets all these conditions. Starting as one of the earliest pioneers along a beach it soon sends its vigorous rhizomes in all directions to gain more area. As the sand piles up and around its many leaves, the vertical stems growing upward force new horizontal branches at different levels in the sand. In other words, a well developed sea-oat colony will consist of underground stems spaced at different subsurface stories. This system, freely branching, at various strata, all connected and with many tough adventitious roots makes a most effective tangle of root and fiber for capturing and holding sands. The rolled-in leaves and tough, drought-resistant stems are not easily shrivelled from drying heat or blast. Waves and wind may undermine colonies of sea-oats; it is not uncommon to see dangling rhizomes, although still connected with the buried portions, alive and poised ready to root whenever contact is again made with a new supply of sand. In fact, all along the coast the highest and most severely blasted crests of foredunes and blow-outs will show the presence of sea-oats. The plant seems adjusted to raw moving sand and is very tolerant of saltspray. Investigating North Carolina coastal dunes Oosting and Billings 23 by trapping and analyzing the amount of salt in the spray borne landward by onshore winds have found that sea-oats are most abundant where the salt content of the air is greatest. In general the air passing over foredunes or the higher exposed back dunes showed the greatest salt concentration and a correspondingly more dominating growth of sea-oats than the lower protected


Plate 1.Dune types related to different plant growth forms.


EXPLANATION OF PLATE 2
Cape Canaveral dune ridges and vegetation. Top: embryonic dunelets sea-oat, right, marsh-elder Iva imbricata, isolated left and down from center. Middle: extreme right and rear row of embryonic sea-oat dunelets; right foreground, convex Iva dune; left foreground, elongated low railroad-vine dunelet. Behind latter a typical ragged sea-oat dune; back of sea-oat to left, Iva and railroad-vine. Bottom: rear dune area; right rear Rolfs'-oak, saw palmetto thicket; center, sea-grape, rear center, saw-palmetto; left foreground, wax-myrtle.
dunes lying in the lee of the higher foredune. Back in old stable sands the sea-oat readily yields to the woody forms, twin live-oak, tough-buckthorn, shore-bay, and yaupon. Of all plants instrumental in dune development sea-oats is the one common species capable of building sand up to twenty-five, thirty, or thirty-five feet. However, other species are not entirely excluded. No matter how firm the dune anchored by sea-oats, there are always small areas left bare in the midst of the most robust and dense colonies of sea-oats. Many herbs, annual, biennial, or perennial, themselves incapable of building or holding a large dune, live and thrive in the sand hills captured by sea-oat. Mindful of this fact, the reader will understand why the diagrammatic profiles of this work show quite a number of species contemporaneous with sea-oats.
Dune Succession
The first impression of the seaside landscape at the Cape Canaveral lighthouse is one of monotony; ridges of sea-oats, clumps of sea-grape, runners of railroad-vines, tufts of grasses, saw-palmettoes in isolated patches with shrubs or thickets farther back. Not much to note it seems. But cross the ridges from beach to rear dunes and sense the rhyme and order of it all. At the front on raw sand and shell are pioneer dune builders, represented by sea-oats, marsh-elder, sea-purslane, Scaevola Plumieri. At the hindmost ridges of mellowed sand have come to stay such shrubs or trees as Rolfs'-oak, wax-myrtle, tough-buckthorn, and shore-bay. There is little mixing between the extremes of unstable front and settled hinterland, but in between are the linking forms, varnish-leaf, saw-palmetto, sea-grape, hair-grass, broom-sedge, beard-grass, which reach ahead and behind. Orderly replacement of one plant association by another is known as plant succession.24 The final plant
a I have made a liberal use of Cowles's classical works on plant succession of dunes.


Plate 2.Cape Canaveral dune ridges and vegetation.


25 "pH" is a symbol used to designate the degree of acidity or alkalinity; pH 7, for example, indicates a neutral reaction. Values less than 7 mean progressively higher acidities; and values greater than 7 indicate alkalinity. In virgin soils readings seldom run higher in acidity than pH 4.5 or possibly pH 4; and seldom a greater alkalinity than pH 8.5,
association that in an orderly vegetational sequence takes possession and that is not replaced by another is called a climax association. The climax association is not replaced except by catastrophic events like denudation by ax, fire, floods, or other violences. Elsewhere on the cape may be found another more luxuriant plant association consisting of forest trees of Rolfs'-oak, mastic, southern red-cedar, red-bay, and black ironwood. This forest was not in direct line with the associations of the profile. Although the writer was not able to make a detailed study, it appears that these forest species or at least some of them represent the climax association of the cape that would on similar but still older ridges replace the last group of species shown at the extreme left of the profile. The story of plant succession and dune building on the cape is in itself an arresting feature.
Species on Sterile and Fertile Sands
Correlation of certain groups of species with two main soil types affords additional interest. Throughout the ridges represented in the profile (PL 3) and in the sand of the climax forest shell fragments or products prevail to the extent of making the soil rich in lime and alkaline or neutral in reaction. These calcareous soils are characterized by the species listed in or pertaining to the profile. Prominent by their absence in that list are slash-pine, spruce-pine, Chapman's-oak, scrub-oak, twin live-oak, rosemary, scrub-palmetto, stagger-bushes, (Xolisma ferruginea and Xolisma fruticosa), tallow-wood, and blueberry. Yet these are the species nearly always encountered in the sterile quartz sand of other dunes and scrub of Florida. About a mile and a half west of the area represented in the profile and the climax forest belt is an area of low topography and slight relief characterized by twin live-oak, scrub-oak, Chapman's-oak, tallow-wood, and blueberry. The coarse sand free of shells testing pH 6.5 to pH 7.5 was apparently not sterile and acid enough for a complete assembly of species characteristic of severely leached sands, yet poor enough to include some as revealed by a brief survey.25


It appears from these and other observations that twin live-oak is the live-oak of sterile acid sands and Rolfs'-oak (possibly only a geographical or environment variety of live-oak as suggested in section on plant descriptions), the one characteristic of rich, more or less alkaline, soils. Likewise it seems that saw-palmetto and wax-myrtle found here in both kinds of sand and common elsewhere in acid wet flatwoods are relatively independent of reaction. The following schematic profile of Plate 3 and of subsequent figures were prepared to present a generalized picture of the relation of the commoner species to the dune topography. The bars underlining the species indicate the range of species.
Plant List
In the order of their occurrence plants 20 in the Cape Canaveral profile are:
Atriplex arenaria Sesuvium Portulacastrum Scaevola Plumieri Iva imbrieata XJniola paniculata Ipomoea stolonifera Sporobolus virginicus Chamaesyce Ingallsii Ipomoea Pes-Caprae Helianthus debilis Raimannia lmmifusa Canavali lineata Andropogon virginicus Coccolobis uvifera Muhlenbergia capillaris Dodonaea jamaicensis Yucca aloifolia Cerothamnus ceriferus Serenoa repens Andropogon glomeratus Bumelia tenax Smilax auriculata Quercus Rolfsii Tamala Uttoralis Baccliaris halimifolia Erythrina arborea Lantana ovatifolia
Beach-orach Sea-purslane t Goodenia (family)** Marsh-elder t Sea-oat
Morning-glory t Rush-grass f Creeping-spurge Railroad-vine Sunflower t
Seaside evening-primrose
Bay-bean
Broom-sedge
Sea-grape **
Hair-grass
Varnish-leaf ** t
Spanish-dagger
Wax-myrtle
Saw-palmetto
Beard-grass t
Tough-buckthorn
Wild-bamboo
Rolfs'-oak
Shore-bay
Groundsel-tree
Red-cardinal
Shrub-verbena t **
26 Because of limited time and opportunity for exploration, the plant lists are concerned only with the commoner and more outstanding species.
t Generic common names.
** Species of tropical affinities.
* According to Penfound and O'Neill.


Iva imhricata
atrmiffx a renting
Sesuvium Portulacastrum ScaevofQ Plumieri_
Uniola panirulata
_Andropogon virginicus
GoccQlobis iiviferCL
Ipomoea stolonifera
Muhlenbergia no pi liar is Dodonaea jamarcensts
CpH 8;
Tama I a littoral is
Co can I obis uvifera
Uniola pgniculata
Andrapagan_virginim*
Muhlenhergia capillar^
__r_Oaa'anaea jg
Oerothamnus ceriferus
inmataensts
Quercus fYo/fsfi
Serenoa repens
Andropogen glomeratus
Burner ia tenax
Plate 3.Cape Canaveral profile.


Other plants to be found at Cape Canaveral are:
Sideroxylon foetidissimum ** Sabina silicola Tamala Borbonia Krugiodendron f err cum ** Quercus geminata Quercus myrtifolia Quercus Chapmanii Ximenia americana ** Cyanococcus Myrsinites t
ties t Blueberry
Mastic
Southern red-cedar
Red-bay
Black-ironwood
Twin live-oak
Scrub-oak
Chapman's-oak
Tallow-wood
JUPITER ISLAND
Northeast of Jupiter lies Jupiter Island, a complex 27 barrier-island about fifteen miles long. The sand and coquina rock belonging to the geological Anastasia formation serves as a foundation for this offshore bar. Where the surf drives spurting water up through tubular solution holes, the rocks are called spouting rocks or bloiving rocks.28 Waves loosening shells and sand from the rock, and winds carrying the product landward from the beach have within recent geological times worked this material into a series of low dunes between the ocean and the lagoon. This lagoon separating Jupiter Island from the mainland is really the southern end of Indian River. Just west of this river spreading inland a mile or two lies a region of fossil dunes.20 Beyond Federal Highway 1 those snow-white dunes mottled with green attain extreme elevations of possibly sixty feet or more.
Two Vegetation Types
A strikingly sharp distinction exists between the vegetation types found on the recent and fossil dunes east and west respectively of the lagoon. The Jupiter profile (PI. 4) represents a cross section running from the beach to the river as found about one mile north of the bridge at Riverside; the west side of the profile refers to the stretch beginning just west of the bridge and continuing to Federal Highway 1. In other words, the
t Generic common names. ** Species of tropical affinities.
27 Johnson, D. W., Shore processes and shoreline development, p. 373.
28 Martens, James H. C, Beaches of Florida, pp. 101-102; Cooke, C. Wythe, Scenery of Florida, pp. 65-66.
so Sellards, E. H., The soils and other surface residual materials of Florida: Florida Geol. Survey, 4th Ann. Rept., p. 74, 1910-1911; Leverett, Prank, The Pensacola terrace and associated beaches and bars in Florida; Florida Geol. Survey Bull. 7, pp. 16-17, 1931.


, PH^ 4.5,4.?
ivri jft< wfi? *W s BJWJ HPS !Ci 13* rtrS TO- !JM
w sra a JmJ**w>kn; cos w
Xolisma fruticosa
Serenoa repens
Quercus Chapmanii
Quercus myrtifolia
Quercus geminata
Pnlyrjanella polygama
Ximenia nmericnna
Iva imhrirata
Chomapsyne huxifolin Ipomoea s to ton if era Mallotonin gnaphalodes
Uniola paniculata_
Scaevoio plumieri _Proton punr.tatus_
Pa/afaxia Feayi
Frnade.a littoraias
Smilay aurinulnta
Caeca lahis uvifera
Pinus r/auso
Cera tio la ericoides
Geobalanus oblongifolius
Sap bar a tarn en Ins a Chrysnhalantis In nan
Serenoa repens_
Garberia fruticosa
Hicnria floridana
Cerothamnus ceriferus Erythrina arborea
Ecastophyilum_Ecasiophyffum


study is continuous from the beach to the highway, but there is an offset at the river.
Between beach and river the calcareous sand supports a robust tangle of saw-palmetto, large clumps of sea-grape, shrubs of wax-myrtle, in general a luxuriant impenetrable scrub thicket dominated by saw-palmetto. Just across the lagoon beyond Riverside the topography rises to about twenty to twenty-five feet in a quarter of a mile. Almost pure white sand runs from the surface to a depth of about three feet. No plant noted on the east side save saw-palmetto was seen in this barren sand. Significant is the fact that Rolfs'-oak found in the alkaline soil of the east side is replaced on the west by twin live-oak, a similar species which is typical of sterile, acid sands.
No analyses are available that are directly applicable to the two soils of the Jupiter section in question. The writer has, therefore, selected tabulated chemical data of comparable soils from Harper30 and from Rogers et al.31 Pertinent figures are
a Harper, Roland M., Geography of central Florida; Florida Geol. Survey, 13th Ann. Rept., pp. 189, 191 and 192, 1921.
3i Rogers, L. H., Gall, O. E., Gaddum, L. W., and Barnette, R. M., Distribution of macro and micro elements in some soils of peninsular Florida: University of Florida Agricultural Experiment Station Bull. 341, pp. 2 and 27, 1939.
Figure 4."Blowing Rocks, iy2 miles north of Jupiter Light. The rock is hard shell limestone, Anastasia formation, which accumulated as a submerged bar during Pamlico epoch." From Cooke, Scenery of Florida, Fla. Geol. Surv., Bull. 17, 1939.


arranged in table 1 into a simplified form, which, it is hoped, will be at least of inferential value.
TABLE 1
SELECTED CHEMICAL SOIL DATA
Foredune f Scrub t Lakewood* Norfolk* Norfolk*
Harper's 1 mi. S. near (cultivated) (cultivated) (virgin)
Melbourne Altoona Manatee Co. Lake. Polk, Lake, Polk,
Beach, Average of Pinellas Pinellas,
Brevard Co. 2 samples Orange, Orange,
Terminology counties Average of 30 samples counties Average of 11 samples
PH 5.70 5.48 5.26
Insoluble S7.3C Insoluble 9S.00 96.77 97.37
Matter Matter
(sand) (sand)
Moisture 5.31 Loss in 1.31 1.71 1.65
(H,0) ignition
Volatile (organic
Matter matter)
(organic)
Nitrogen .157 .02S Nitrogen 0.03S 0.049 0.033
Potash .014 .003 Potassium 0.01 0.04 0.04
(K,0)
Lime 1.25 .030 Calcium 0.08 0.13 o.u
(CaO
Phosphoric .130 .OOS Phosphorus 0.02 o.os 0.03
Acid
* Harper. 13th. pp. 191-192. Table IS, Sample 2.
J U. S. Soil Bull. 13 per Harper. Table 17, p. 189, 13th, Sample D.
* Rogers et al., p. 12, Table 1, Appendix pp. 2f-26, Data represent surface soils.
The reader will note that the percentage of chemical constituents and organic matter runs higher in the dune sand of Harper's table than in the Lakewood which is low in bases but high in insoluble matter (sand). The soils of the recent dunes of Melbourne and Jupiter are very similar in that both are characterized by sand and shells derived from coquina. We may, therefore, assume that the relative fertility of the Melbourne sand holds for the Jupiter shelly sand.
The Lakewood sand of Rogers and the Altoona scrub sand of Harper show very low percentages in all chemical elements and in humus, but a high proportion of insoluble material. These soils are, therefore, considered poor or sterile. The Lake-
EXPLANATION OF PLATE 5 East coast dunes of Jupiter and Crescent Beach. Top: Jupiter foredunes formed from disintegrated coquina. Note rock outcrop. Conspicuous plant at left foreground is Scaevola Plumiera. Middle: Fossile dunes west of Indian River at Jupiter. Vegetation: spruce pine, the three oaks of dune and scrub-twin live-oak, scrub-oak, Chapman's oak and rosemary in foreground. Ocean in rear. Bottom: Crescent Beach, showing four parallel dune ridges. The first at extreme right marked and shifting sand; the second ridge between the latter and figure; third ridge, with figure; the fourth at extreme left dominated by saw-palmetto. Vegetation: sea-oats and saw palmetto.


Plate 5.East Coast dunes of Jupiter and Crescent Beach.


wood data are of cultivated soils of Manatee County, but neither the different site nor the cultivation should invalidate the applications of these percentages to the Lakewood soil west of the Indian River as considered in the Jupiter profile. The white Lakewoods are so constantly sterile and acid, so habitually poor in humus, and so typified by scrub vegetation that the author feels safe in applying the data of Manatee County to the white acid sand supporting the scrub just west of the lagoon. Moreover, Rogers' data show no significant difference in the chemical content between cultivated and virgin soils of Norfolk sands which are very similar to Lakewood sands and almost as poor. The Lakewood data of Manatee County seem, therefore, to offer a fairly representative pattern of the Jupiter Lakewood scrub.
The foregoing seems to establish that the presence of distinctive assemblages of plants of the recent and fossil dunes at Jupiter is tied up with different soil types. But there is still another aspect to the singular plant distribution of this area. While the barrier-island offers habitat to a number of plants pretty generally found on Florida coasts, it harbors also a considerable number of species of tropical origin. Using Small's manual32 the writer has presented the geographic ranges of the species and marked those of the tropical affinities with an asterisk in the Jupiter plant list. At home in southern Florida, on the Keys, and in the West Indies the tropical species reach their northernmost limits on these coastal offshore bars. Small in noting this coastal aggregation of tropical plants pushed out of range northward offers the following explanation: "The tropical elements were brought northward long ago in some way and maintained there, evidently, by the proximity of the contiuously warm water of the lagoons." M3 However important the moderating effect of the lagoons as well as the Atlantic Ocean itself may be this explanation hardly provides for the sharp distinction of the vegetations that exists on the two terrains immediately to the east and west of such a narrow lagoon as the Indian River which at Riverside near Jupiter is only one or two hundred feet wide. Harper with another point of view observes: "The plants growing on shell mounds along the Indian River in southern Brevard County are nearly all of tropical species, quite different from the species of more north-
*2 Previously cited. See footnote 20, page 22.
as Small, J. K., Coastwise dunes and lagoons: Jour. N. Y. Bot. Garden 20: p. 197. October, 1919.


erly distributions on sandy soils nearby." 31 The same plant geographer speaks of the tropical aspect of the flora on old shell mounds on the barrier-island east of Melbourne and on a coquina bluff just south of Fort Pierce.
At Cape Canaveral near the lighthouse where the studies for the profile of that section were made a number of southern species (marked with asterisk) are in evidence on the shelly sand. In a calcareous hammock :iS a few miles south of the lighthouse apparently developed on old low beach ridges two tropical trees were commonmastic and black-ironwood. Very different are the acid sands, devoid of shells, where in place of southern species one finds a scrub vegetation of wide distribution in the State. Harper's observations and the distributional facts relating to Jupiter and Cape Canaveral of this study point to the conclusion that the long narrow coastal bars with their cores of coquina and its derivative (shelly dune sands), or shell mounds by man, all more fertile than siliceous sand, make it possible for tropical species to stretch their range northward along the coast. It must be obvious that locally the nature of the soilquantity of minerals, reaction, (acid or alkaline) organic matterplays the important role in accounting for the overlap of southern and northern species.
In passing, the writer calls attention to the conclusions of Wherry. Discussing the relations of many native herbs of eastern North America to soil reactions, he states "that it seems safe to state that in eastern North America, as a general rule, in any group of closely related plants those of southern distribution are likely to favor more acid soils than northern or western ones." In support of this he writes:
". . many of the more Northern plants, which were among the first to reoccupy the glaciated regions of northern North America, survived glaciation in regions of circumneutral soil, for the soils
34 Harper, Roland M., Geography of central Florida, p. 205. The other related observations by Harper are found in the same reference pp. 147, 179, 205-206; and in Natural resources of southern Florida: Florida Geol. Survey, 18th Ann. Rept, pp. 106-108, 1927.
as "The term 'hammock' has a rather broad meaning, but as generally used refers to the growth of hardwood. However, it often goes further, in that there must be leaf mold and the soil darkened by the content of humus. The tree growth consists mostly of live-oak, water-oak, white-oak, hickory, magnolia, and in the more moist places bay, gum, black ash, and cabbage palmetto, and there is a rather thick undergrowth of other vegetation." Mooney, Charles N., Latimer, W. J., Gunter, Herman, and Gunter, Emil, Soil survey of the Ocala area, Florida: Florida Geol. Survey, 7th Ann. Rept., p. 207, 1915.


Wherry, Edgar T., Divergent soil reaction preferences of related plants: Ecology, vol. 8, no. 2, pp. 204-205, 1927.
37 Harper, Roland, Natural resources of southern Florida, p. 54; Lev-erett, Frank, The Pensacola terrace, pp. 16-17; and Sellards, E. H., The soils of Florida, p. 71.
38 Cooke, C. Wythe, Scenery of Florida, pp. 51, 64-65. so Ibid, pp. 65 and 51.
40 ibid., p. 34.
left behind upon the retreat of an ice sheet are rich in bases and correspondingly circumneutral in reaction; while the plants we term southern are the ones which survived the Glacial Period in parts of the southern Appalachians and the Coastal Plain, where the soils from long exposure to leaching had become, prior to Glacial times, extensively if not dominantly acid."
Reflection on this statement makes it seem that Wherry's acid species of the southeast are bounded on the north by circumneutral base preferring survivors of the Glacial Period on the southeast coastal dune strip of Florida by another set of circumneutral, lime or base preferring species hailing from the tropics.
Geological History
Turning back to the distributional phenomenon at Jupiter, one wonders why the slender lagoon should be the line of cleavage between such distinctive soils found there each with its unique plant association. The answer lies in the geological past. At one time the ocean shoreline was farther inland; presumably the west bank of the Indian River lagoon was once the ocean beach.37 While the seashore was at this site, sands of that ocean beach were being worked into dunes west of Indian River. And according to Cooke 38 about this time the Anastasia formation, in part the coquina rock of today was accumulating "as a succession of slightly submerged bars loaded with shell remains when the sea level stood 25 feet higher than now during the Pamlico epoch." Jupiter Island of today was then outlined as an offshore bar. The quoted authority asserts that the bedding of the rock dips seaward like deposits of modern beaches.30 Next, at the close of the last glacial (Wisconsin) stage, the sea retreated to its present shore.40 The offshore bar emerged as Jupiter Island. More or


less concomitant wave and wind action dissembled the coquina into shell and sand, working the detritus into the dunes of today. And so the course of geological ages has culminated with two floras, dovetailing on modern and ancient dunes set apart by a lagoon.
Plant List
Sea-oats zone Iva imbricata Ghamaesyce buxifolia ** Mallotonia gnaphalodes ** Ipomoea stolonifera Uniola paniculata Scaevola Plumieri ** Groton punctatus Achyranthes maritima Helianthus debilis Groton Fergusonii Ipomoea Pes-Caprae
Palmetto zone
Ernodea littoralis ** Goccolobis uvifera ** Sophora tomentosa ** Ghrysobalanus Icaco ** Serenoa repens Erythrina arborea Gerothamnus ceriferus Quercus Rolfsii
Ecastophyllum Ecastophyllum u Randia aculeata ** Lantana ovatifolia ** Baccharis halimifolia Icacorea paniculata ** Echites Echitea **
Scrubwest of River Xolisma fruticosa Serenoa repens Quercus Chapmanii Qtiercus myrtifolia Quercus geminata Ximenia americanus ** Palafoxia Feayi Smilax auriculata Pinus clausa Ceratiola ericoides Geobalanus oblongifolius Hicoria floridana Garberia fruticosa Cassytha filiformis **
Marsh-elder | Spurge | Sea-lavender Morning-glory Sea-oat
Goodenia family Silver-leaf croton Chaff-flower t Sunflower f Croton % Railroad-vine
Madder family
Sea-grape
Necklace-pod
Cocoa-plum
Saw-palmetto
Red-cardinal
Wax-myrtle
Rolfs'-oak
Pea family
Madder family
Shrub-verbena
Groundsel-tree
Marlberry
Devil's-potato
Stagger-bush
Saw-palmetto
Chapman's-oak
Scrub-oak
Twin live-oak
Tallow-wood
Thistle family
Wild-bamboo
Spruce-pine
Rosemary
Gopher-apple
Scrub-hickory
Thistle-family
Love-vine, a parasite
** Species of tropical affinities, f Generic common names.
t Departure from Small's manual, as to common name.


Cornish, Vaughan, On the formation of sand-dunes, pp. 293-294.
Figure 5.Dunelets elongated parallel with wind direction. Santa Rosa Island near Camp Walton. From Martens, Beaches of Florida, Fla. Geol. Surv. Twenty-firstTwenty-second Ann. Rept., 1931.
crescent beach
Formation of Dunes
Striking parallelism and symmetry mark the dune ridges of Anastasia Island, an offshore bar. The locality represented in the profile (PL 6) is three miles south of Crescent Beach, St. Johns County. The first three ridges, linear and nearly even-crested rows, gain in progressive height to a maximum of approximately twenty feet. A fourth ridge hardly as tali as the third, although considerably wider and flatter shows nevertheless obvious conformity to the others. From the fourth ridge to a distance of about four hundred feet a confusion of sand knolls and hollows replace the order of the fore ridges. Extending from this gently irregular zone to the swamp six hundred feet away lies a low sandy terrain. Several aspects of these dunes provoke curiosity. Why, for instance, are these ridges so nearly parallel to the shoreline and to each other but at right angles to the sweep of the onshore winds that blow across the shore and land?
According to Cornish41 shore dunes may be elongated with


fun imhrirnfa
Sporting patens_
Ipnmofin Pes-Caprae
Helianthus debilis
IJnio/a panicu fata
Raimannin humifusa
Rumelia tenax
Serenaa repens
Hex vomitnria
Cerathamnus ceriferus
Quercus geminata
Tamata littoralis
Xnlisma ferruginea
Pteridium aquilinum
Cyanocnccus Myrsinifes pyemic Chapmanii_
Quercus myrtifolia
Plate 6.Crescent Beach Profile


42 Ibid., pp. 289-290.
the line of movement where the winds are strong enough and the loose sand supply meagre; he says in effect that where the "wind has mastery" of the sand coastal dunes clearly show a longitudinal development. Small embryonic dunes are sometimes elongated but a copious sand supply soon produces a merger of individual single dunes into one wide transverse ridge. However, in the prosecution of this work the writer has seen nothing more suggestive of "stripe" dune development than what can be seen in figure 5 by Martens taken on Santa Rosa Island. Turning again to Cornish 42 one finds that with moderate winds and plenty of loose sand even dunes of deserts tend to form as ridges drawn across the wind. In other words, abundant sand and wind of the proper velocity could in themselves account for dunes paralleling the Florida coasts; but another cooperating and more important circumstance than velocity of wind and abundance of sand is the fact that the sand supply itself is an elongated belt.
Dried on the upper beach and driven by the onshore winds, this belt of sand advances landward with a broad frontal movement. The importance of this frontal line advance is somewhat obscured by the fact that vegetation soon pounces on the emerging beach where debris heaped in rows affords lodgment of seed and subsequent foothold of plants. With pioneer herbs marshalled in line, a continued sand supply, and onshore winds, the building of the foredune proceeds parallel to the shoreline and towards its final altitude. Every ridge farther back was once a foredune; all ridges will therefore be parallel to the ocean front and to each other.
The ultimate elevation of a dune ridge is the composite result of many elements. Some of these factors, physical in nature, are sumarized in table 2.


TABLE 2
SOME FACTORS OPERATIVE IN DUNE ALTITUDE
Factors favoring increase of Factors opposing increase of
altitude altitude
(Building up, construction) (Tearing down, destruction)
Wind
Moderate or weak air currents Stronger upper air currents re-transport sand upward the wind- move sand from top. ward slope. Erosion >.'
Aggradation
Gravity
Favors erosion and is in direct relation to density of particles moved. Opposes aggradation.43
Sand Supply
Continued sand supply Terminated sand supply.
In turn depends on
(a) Continued shore current replenishing sands cast ashore.
(b) Erosion elsewhere to fur- nish sand to current. (Review Cape Canaveral.)
(c) Strong wave action to wash up and deposit sand on higher back beach.
In turn depends on
Deep offshore bottom favoring strong surf or on exposure to open sea.
(d) Age of shore, young shores having little or limited supply, while older ones tend to have a more copious amount. 44
Time
Prolongation of time of action ob- Converse evident viously tends to increase the height slight settling disregarded.
Exposure
Open exposure favors strong wave Shelter reduces power of waves and wind action.44 and wind and therefore their
ability to transport sand.
Beach Stability
Stability of beach, actual or rel- Widening of beach or prograding ative results in long continued shoreline results in new fore-
actions which concentrate sand dunes which in turn
on a given dune ridge.45 (a) Reduce the time of action
on any one ridge, (b) Intercept sand headed for the back ridge.^e
Ibid., p. 285.
4 Johnson, D. W., Shore processes and shoreline development, pp. 440 and 451.
45 Cressey, George Babcock, The Indiana sand dunes, p. 39. 40 Ibid.; and Johnson, D. W., op. cit., p. 451.


4t Cressey, George Babcock, op. cit., p. 39.
The sum total of all the forces at play in building a dune to its final height is well stated by Cressey:" ... a maximum and roughly uniform height is established by an equilibrium between the ability of the surface winds to move sand up the dune and the erosion force of the higher winds."17 In analyzing this statement the reader will readily see that ability of wind to move sand up the slope is hindered both by gravity and by vegetation; whereas the ability to remove sand at the top is hindered by vegetation but is aided by gravity. Vegetation slows the velocity of the wind. As a result, the wind loses power to move sand up the slope and drops its load. But plant roots and stems also anchor sand; thus vegetation helps the dune to hold what it does gain by the weakening that it imposes on the wind. One of the main objectives of this work is to bring out the importance of plants in covering, anchoring, shaping, building, and stabilizing dunes; nevertheless, nothing has appeared in the pursuance of this work that indicates definitely to what altitude dunes are aided by vegetation, and at what elevation they are handicapped or neutralized by plant growth.
Sea-oat is found on even the highest modern dunes. Other factors being favorable to a dune's growing higher could the plant climb up with it and survive on an elevation greater than thirty-five feet? It seems so. From another point of view it appears that with increasing altitude to a lengthening slope come more and more sea-oats which by their very presence throw so many hurdles in the path of the wind that a maximum is reached at which there is no gain in sand. About all that can be ventured relative to the maximum height of Florida's coastal dunes is that it depends on an interplay and balance of many factors including vegetation and the conditions that influence the rapidity and luxuriance of its growth. The sum total of all interplaying factors brings these foredunes up to an elevation of ten to twenty-five feet, possibly thirty-five or forty feet. Blow-outs, considered further on, reach altitudes of thirty-five to forty feet at Ponte Vedraexceptional values for foredunes.
A feature of the coastal dune stature is that there is one ridge usually towering over the others. At Crescent Beach it is the third ridge. (See plate 5). It is almost self-evident that


the lower altitude of the first two ridges is tied up with their recency; but the elevation of the third to its conspicuous height might conceivably have involved one or more physical factors like sand supply, duration of beach at one halting placeit is almost vain to specify any one particular factor. Johnson states:
"Successive beach and dune ridges normally differ from each other in altitude of crest line. This follows from what has already been said regarding the origin of such ridges. A temporary excess of shore d6bris may cause a new ridge to form before the earlier one behind it had acquired any considerable altitude; and the new ridge may rise to a great height before the development of a still later ridge checks its growth. Temporary retrograding of the shoreline may combine several low ridges into one high one, while earlier and later ridges remain of moderate altitude. The great variability of the marine forces causes the successive positions of the shoreline to be maintained for unequal lengths of time, and to have unequal quantities of shore debris cast into shore ridges of unequal height. It may happen that one ridge is not raised above water level before another is built in front of it, but as a rule the differ-nces in height are all to be measured above the level of the sea." is
This one large ridge, however formed, because of the shelter that its superior height provides to plants on its lee plays an important role in the vegetational aspects of the dune topography behind.
More or less uniform crests typical of foredune ridges are quite pronounced at Crescent Beach. If one can imagine a gigantic straight edge (aggrading wind) pushing the sand up the windward slope by broadside movement; if he can also think of another linear edge (eroding wind) scraping across the top with vegetation tending to stabilize, he can understand the relatively even crests of the ridges.
Dune Erosion
The presence of three or four ridges successively smaller toward the shoreline indicates that within recent geological time the beach has been building up and advancing oceanward; recall Cape Canaveral. But there is here to note another interesting phenomenon: the youngest ridge is marred by an almost vertical wave cut cliff. This small sand scarp shows a still more
48 From Shore Processes and Shoreline Development (pp. 440-442), copyright 1919, by D. W. Johnson, and reprinted by permission of John Wiley and Sons, Inc., Publishers, New York.


recent slight encroachment of sea coast on the coast line. Figure 6 shows such a wave-cut scarp in sand.
In connection with the Ponte Vedra profile this discourse deals with a more spectacular case of dune erosion; it may be well, therefore, to offer an explanation of this apparently simple thing of nature. Florida's east coast shoreline is one of emergence;19 that is, the coast along with the whole Coastal
Figure 6.Wave-cut sand scarp south of Ponte Vedra. Note interlacing tangle of stems and roots of under-cut sea-oats and wave-deposited sea-weeds at right.
Plain has within recent geological times risen. Johnson holds that "waves can and do cut into the offshore bars of a shoreline of emergence whenever that shore remains stationary long enough, or rises more slowly than the waves cut in, or experiences submergence." This same authority points out that in the South Atlantic Coast including Florida's east coast there has been no important change in the relative level of land and sea in the last few thousand years. While this relatively long sustained stability probably explains wave erosion of wind formed dunes, it does not preclude also the possibility of cutting induced by slow emergence or even slight or local submergence.
4 Personal communication from D. W. Johnson; and Martens, James H. C, Beaches of Florida, p. 79.


In any event shore erosion of this kind plays havoc with pioneer dune vegetation. In fact, at Ponte Vedra and other coastal points undermining waves are bringing disaster to old and long established cabbage-palms and forest trees.
Blow-outs
Along this wave attacked low fore ridge there crowds into view another arresting sight: heaped over and just to the upper edge of the scarped ridge is considerable new sand, striking by its light colora strong contrast to the maze of green sea-oats a little farther back. These mounds of sand accumulating on top of the small, but partially or temporarily stabilized, dune are the products of incipient small blow-outs. In their most exaggerated expression blow-outs cause catastrophe to dunes, to vegetation, and even to the works of man. Martens has expressed the opinion that goats and cattle uprooting sea-oats aid the wind in starting blow-outs and thus help to bring about the annihilation of seaside vegetational scenery. According to Oosting and Billings grazing may turn even dunes bound by such effective plants as sea-oats into a "sea of shifting sand." 50 A trivial circumstance may start one: a kick, an uprooted plant, a hole may loosen sand which upon drying is easily picked up and removed by wind. At Crescent Beach for instance the waves are undermining the sand for the sun and wind. Undercutting by waves and wind accomplishes two important things: a greater amount of loose sand is made available for removal; and channels or troughs are scoured where air currents concentrate and gather force. Stronger winds in turn scour, expose, and provide more loose sand for removal; and so on. This increased sand supply and the stronger air currents may drive and pile these rejuvenated dunes faster than vegetation can capture or anchor them; consequently, blow-outs, often higher than foredunes, are overwhelming to plants or things that happen to lie in their line of march. Although small in proportion, these blow-outs at the wave cut ridge offer a modest preview of the more spectacular ones at Ponte Vedra.
soMartens, James H. C, Beaches of Florida, pp. 92 and 119; and Oosting, Henry J., and Billings, W. D., op. cit., p. 141.


Stream-lined Vegetation
This series of ridges illustrates the influence of natural wind breaks and severity of blast on the development of vegetation. The first ridge is lush with sea-oats interspersed with a few marsh-elders, seaside evening-primroses, railroad-vines, and others. Sea-oats seem to flourish and fruit directly in proportion to the severity of the blast, spray, and recency of sand heaps. From the first to the fourth ridge there is a very orderly decline in robustness, in number, and in number of plants in flower. Hard conditions often encourage plants to bloom; but the heavy population and great size of the plants indicate that sea-oats is here not adversely affected.
Sheltered in the swale behind the second ridge are saw-palmetto and tough-buckthorn. The incessant wind shears the tops and clips the leaves of the latter so that they stand almost unnoticed behind the ridge. Their seared and leafless twigs reflect the hard conditions above this swale; still, a number of established but dwarfed specimens seem to hang on. The trough to the lee of the third ridge harbors tough-buckthorns up to seven feet high which the wind driving across the crest streamlines evenly with the top of the dune. Some buckthorns are seared by wind above and smothered by wild-bamboo below. Interestingly enough, this bamboo clambers all over yaupons, tough-buckthorns, and twin live-oaks but all of the aromatic shore-bays seen here were entirely unmolested by it. In the higher areas of the more or less undulating fourth ridge, it is common to see a palmetto not so sensitive to blast sheltering a wax-myrtle or tough-buckthorn to the lee as tall as itself. From ridge four on, and correlated with diminished shore winds, appear larger but still stream-lined, wax-myrtles, shore-bay, and tough-buckthorn, twin live-oaks, and yaupons. In the low sands following the gently rolling dunes behind ridge four, the shrubs and trees attain heights of ten to fifteen feet. Although really large in relation to the woody plants nearer the beach, they are still in the category of wind-clipped dwarfs. All of these plants give the impression of leaning away from the seaside.
EXPLANATION OF PLATE 7.
Stream-lining on the seacoast. Top: live-oak 5 miles south of St. Augustine, State Highway 140. Middle: magnolia dune remnants in blow-out at Panama City Beach, Bay County. Bottom: oak scrub, cabbage-palm, saw-palmetto, fossil dune about 25 feet high, Manhattan Beach, Duval County.


Plate 7.Stream-lining on the seacoast.


Bumelia tenax Serenoa repens Iva imbricata
Uniola paniculata
Sea-oat
Tough-buckthorn Saw-palmetto Marsh-elder t
t Generic common names
It is really not an actual drawing inland by the wind. What takes place is that young tender shoots which are directed toward the beach or up beyond the shelter are killed by the wear of the wind, salt, and sand. The twigs headed inlandward on the sheltered side of the tree itself are permitted to develop. The asymmetrical growth form of these trees is, therefore, brought about through the action of the wind in killing back all the twigs headed into exposure. Most of the woody plants in these exposed situations present a solid smooth exterior of crowded foliage. Like a gigantic pruning shear the winds trim back the young twigs. This natural shearing only induces more buds to develop into stems which in turn bring their leaves to a common surface. Any shoots that grow beyond are soon destroyed. There are areas along the east coast where the dwarfed shrubs are so closely interwoven, so evenly clipped that the surface will not betray the length or diameter of the gnarled stems that support the bruised screen of leaves and twigs. In some places a solid surface of leaves, because of diminishing force of wind, rises higher and higher inlandward. So solid appears the neatly trimmed foliage and so misleading the uphill effect that the writer has started into such thickets expecting to climb a dune only to find himself on the brink of a lee and to look into a hammock of trees below. What was mistaken for shaven shrubbery "up the hill" and in the rear was a solid canopy of tree tops.
At Crescent Beach between the gently irregular dune zones, (Stations marked 5-6 in profile) terminated by the ridges and the swamp farther back, lies a low area (Station 7) with dark coarse sand dominated by wax-myrtle, saw-palmetto, twin-oak, stagger-bush (Xolisma ferruginea) and supplemented by blueberry and bracken with scattered scrub-oak and Chapman's-oak. Noteworthy is the fact that in this wet acid sand free of shells saw-palmetto yields more ground to competitors than it does in the shell laden sand at Jupiter.
Plant List
Sea-oats zone
Ipomoea Pes-Caprac Railroad-vine
Helianthus debilis Sunflower!


Bivonca stimulosa Raimannia humifusa Chamaccrista brachiata Spartina patens Sporobolus virginica
Spurge-nettle
Seaside evening-primrose
Sensitive-pea t
Salt-grass
Rush-grass t
Scrub zone
Ilex vomitoria Cerothamus cert ferns Quercus geminata Tamala littoralis Xolisma ferruginca Quercus Chapmanii Quercus myHi folia Pteris latiuscula Desv. Cyanococcus Myrsinitcs Smilax auriculata Serenoa repens Zanthoxylum Clava-Herculis Geobalanus oblongifolius
Yaupon
Wax-myrtle
Twin-live-oak
Shore-bay
Stagger-bush f
Chapman's-oak
Scrub-oak
Bracken
Blueberry f
Wild-bamboo
Saw-palmetto
Toothache-tree
Gopher-apple f
DAYTONA BEACH
On the ocean front just north of Daytona Beach lies a complete set of dunes running from the sea-oats of the foredunes near the ocean to disturbed hammock one-half mile west against the Halifax River. Although more or less disturbed in the interest of residential and beach developments these dunes when studied presented a fairly complete picture of vegetational changes as related to dune development. However, the native vegetation and natural scenery of some of the very area included in' the profile have since been destroyedforever. The tragedy to economic and scientific interests as well as to present recreational values appears in the form of neglect to capture and preserve for public welfare at least some of these all too rapidly disappearing landscape features known as sand dunes. Setting aside undisturbed fully representative strips of coastal dunes, fashioned by the processes of ages, would represent long range economy and wisdom. The public is entitled to natural grounds for recreation and study. Engineers, scientists, and naturalists require unmolested tracts as guides for future action on coastal projects or problems. The past has seen along the coast too much highway construction and improvement which ignored shore processes. As a consequence long stretches not only have been rendered unsightly, but have also been poorly constructed on unstable foundation so that they are in constant danger of sand burial.
t Generic common names.
* Small, J. K., Ferns of the southeastern states (1938).


Shoreline Features
At Daytona Beach the steep sand cliffs (Marked stations 2 and 3 in Plate 8) testify to the fact that the shoreline is encroaching on the dunes. Wave as well as wind action is more pronounced than at Crescent Beach farther north. Blow-outs are more vigorous (Station 1) and the windward slopes (Stations 2-3) because of storm tide action are very steep with an angle of about 30 . Where sand supply is ample, the windward slope seldom exceeds 10 to 15 degrees. If the present shoreline processes continue, the foredunes face final destruction. The whole coast at this section is a long barrier-island. Barriers of this type, Johnson M has pointed out, are ultimately destroyed by the very kind of waves and wind that created them. Normally destruction begins from the moment of initiation. The process seems here well underway. High water undercutting, wind rolling the sand back, and sea-oats pinning down produce here a staircase type of profile. From station 4 back to 6 there is not a great difference in the gentle rolling topography or in the level; but in this half-mile stretch there necessarily is represented a considerable space of time to lay the ridges down from quiescent mellowed sandhills back at the Halifax on forward to the modern picturesque ridges facing the Atlantic. The raw sand at the front is alkaline; whereas farther back the white surface and yellow sub-surface sand indicating maturity reacts acid and carries locally an abundance of humus in the surface soil.
Succession
The orderly manner in which sea-oats at the front are replaced by scrub thicket behind, the thicket by spruce-pine, and the latter by the final hammock is something to be remembered. In this general picture are interesting details. For one thing, the sand, less laden with alkaline shell material than farther south at Cape Canaveral or north near St. Augustine, has become leached enough to provide favorable soil for the spruce-pine. Harper5* has observed the partiality of this pine for poor soils. Leached sands seem necessary for this tree, but it will grow in neutral or slightly acid soils as well as in more highly acid ones. The heaths entirely absent on the shell-loaded
ri Johnson, D. W., Shore processes and shoreline development, p. 382.
Harper, Roland M., Geography and vegetation of northern Florida: Florida Geo. Survey, 6th Ann. Rept., p. 244, 1914.


low dunes of Cape Canaveral are here represented by stagger-bush (Xolisma ferruginea), blueberry, and sparkleberry. However, a slight acidity (pH 6.5) suffices for their growth. Anyone alert to sights and scenes along the coastal highway will notice with what constancy spruce-pine leans away from the ocean. It is not altogether a case of strong prevailing onshore winds chopping off growth on the ocean side of the trees. The trunks actually tilt toward the land. Spruce-pines will lean where slash pines stand erect. The strength of the wind is not entirely responsible. The shallow roots of this species anchored in a loose sand provide the answer. Sometimes the spruce-pine forms colonies so dense that practically nothing can survive in their shade. In places like this the gathering needles make a surface rich in decaying litter and humus.
Locally, where the shade is not too great, bracken fern fronds grow five feet tall, much larger than one ordinarily sees them, common as they are in the State. World-wide in distribution, the bracken nevertheless exhibits some puzzling local preferences in habitat. In the Midwest the fern grows in sand acid or alkaline. Sometimes as in Iowa County, Iowa, one finds it in very local ancient dune sands of the Iowa River. And just about the time its correlation with sand and only sand is made the plant turns up on the other side of the river in forests growing on the clay or silt loams. In Florida, however, it is common enough, plants of moderate stature being almost any place where there is sand or sandy clay.
The intense shade of crowded spruce-pines may exclude everything even their own offspringand certainly the oak species which it supercedes. From the darkest middle of a grove the writer has seen saw-palmetto radiating outward in all directions towards a surrounding circle of light. As the trees get taller and under-branches slough off, light filters in. Then come in cabbage-palms, magnolias, red-bay, small-fruited pawpaw, holly, and pignut. Even twin live-oak, scrub-oak, and Chapman's-oak once driven out may steal in again. In this beginning hammock the twin live-oak may now develop into a luxuriant treequite in contrast to the stunted form of the wind-driven scrub that antecedes the spruce-pine stage.
At the extreme hinterland of this dune sequence subdivision developments of the past have wrought catastrophe to the natural stand of trees. But remnants indicate a climax forest


the last word that vegetational development writes. Some of them old and large the chief species are: magnolia, cabbage-palm, twin live-oak, holly, red-bay, wild-olive, small-fruited pawpaw, French-mulberry. Throughout the stages of succession from the lee of the tall barrier dune to the incipient or mutilated climax runs the versatile saw-palmetto.
Plant List
Sea-oats zone
CaTcile edentula Iva imbricata Raimannia humifusa Ipomoea Pes-Caprae Uniola paniculata Ipomoea stolonifera Croton punctatus Bivonea stimulosa Chamaecrista brachiata
Scrub zone
Serenoa repens Bumelia tenax Quercus geminata Quercus myrtifolia Quercus Chapmanii Cerothamnus ceriferus Sabal Palmetto Xxmenia americana Batodendron arboreum Sabal Etonia Cyanococcus Myrsinites Pteris latiuscula Desv.*
Spruce-pine hammock Tamala littoralis Pinus clausa Amarolea americana Xolisma ferruginea Ilex vomitoria Smilax Bona-Nox Zanthoxylum Clava-Herculis Sabal Palmetto Magnolia grandiflora Callicarpa americana Tamala Borbonia Asimina parviflora Parthenocissus quinquefolia Toxicodendron radicans Ilex opaca Hicoria glabra
Sea-rocket t
Marsh-elder t
Seaside evening-primrose
Railroad-vine
Sea-oat
Morning-glory t Silver-leaf croton Spurge-nettle f Sensitive-pea f
Saw-palmetto
Tough-buckthorn
Twin live-oak
Scrub-oak
Chapman's-oak
Wax-myrtle
Cabbage-palm
Tallow-wood
Sparkleberry
Scrub-palmetto
Blueberry t
Bracken fern
Shore-bay
Spruce-pine
Wild-olive t
Stagger-bush t
Yaupon
Bamboo
Toothache-tree
Cabbage-palm
Magnolia $
French-mulberry
Red-bay
Small-fruited pawpaw
Virginia-creeper
Poison-ivy
Holly
Pignut
t Generic common names.
?Small, J. K., Ferns of the southeastern states (1938) t Departure from Small's manual, as to common name.


Serenoa repens
Quercus gem/nolo
Quercus myrtifotia
Cerothamnus ceriferus
Sabal Palmetto
Tamala_littoral is....
Quercus Chapmanii
Pinus clausa
A maro tea americana
Xolisma ferruginea
Cafticnrpa americana Magnolia grandiflora Tamala Rorbonia
Cakile -edentu/o iva imbricata Raimannia humifusa Ipamoea Pes-C.aprae
Uniola paniculata_
Ipomoea sfolonifera___
Rumeliatenax
Plate 8.Daytona Beach profile.


VILANO BEACH
This study was made on a seven-mile segment beginning seven miles north of Vilano Beach, St. Johns County. On these barrier-island dunes erosion, as at Daytona Beach, shows up as two or three successive steep sand cliffs facing the ocean. Blow-outs
Dead tumbling oaks point to a far advanced shoreline encroachment on dune and trees. The exposure of dead oaks, tough-buckthorn, and shore-bay indicates a former stability that could only have been attained when greater distance from the beach and interposed ridges, now erased offered shelter from winds and waves. The fallen oaks probably once grew in the protection of a depression or lee of a dune. By blow-out processes described before, the forces of water and air are even now driving or rolling the fore ridges back on themselves as it were. The blow-out factors here, an exaggerated repetition of Crescent Beach and Daytona Beach, are throwing sand on and increasing the height of what was already a prominent ridge. In a personal communication Johnson explains:
". . where waves are cutting into a coast that was formerly built forward by successive beach ridges, there is a tendency for the eroded material to be in part thrown upon the edge of the land to form a prominent ridge which may be still further increased in height by dune sands blown upon the ridge by winds traversing dry beaches."
Removing sand from the fore and throwing it over the lee results in an actual inlandward migration of the dune. Advancing sand is smothering woody plants now alive but destined to perish and to lie exposed as plant skeletons on a future face of eroding cliff or blow-out. Retrogression
In the dune activity witnessed here there is no orderly appearance of successively new ridges. Waves, wind, and plants do not work in full partnership to create a dune and plant succession by gradual progression. Action here is retrogressive. Potential stability becomes an upheaval through the agency of tearing waves and shifting winds. Plants are killed by catastrophic changessmothering, tearing, uprooting of leaves, stems, and roots. Where dunes are building, woody plants follow up the herbs, keeping always to a certain ridge or trough in the rear: it is a case of isolated shrubs venturing, pioneering into the new dunes. Here, where destruction rules,


the reverse is true: it is not a question of what species will be the first to venture on a younger dune; it is rather the problem of what species will hold on the longest. It is not a case of coming in first; but, of going out last.
On the protected side of the ridge twin live-oak, tough-buckthorn, and shore-bay are competing nip and tuck. The saw-palmetto, not well adapted for rapid changes, also hangs on in milder conditions. Once the stunted growth was relatively luxuriant; now by extreme exposure on top there are many twigs weather-beaten and stripped of leaves. Behind the ridge woody species, like twin live-oak, tough-buckthorn, and shore-bay, display a crisp green foliage below the level of the crest. Higher up, the wind cuts the plants down to a plane even with the top of the ridge. Prom here on back a streamlined vegetation with a hump effect in the lee of every ridge and closely cropped tops on every windward side is very evident. Of course, the farther away from the foredunes the ridges are, the more uniform in height is the vegetation. However, the swales, because of greater moisture and protection from wind, tend to have trees and shrubs of higher stature. Here and there on the rear ridges magnolia with dark green shiny leaves makes a conspicuous appearance. Succession
We spoke of retrogression at the foredunes; but from the large foredunes toward the rear, successive types of plant associations replace one another in the usual intergrading manner. Very gradually species fall out and others step in to replace them. But in spite of the dovetailing of species in adjacent zones, ridges farther apart show definite changes in species content. This is noteworthy: while shrubs like wax-myrtle and stagger-bush {Xolisma ferruginea) reach the uncommon height of twelve to fifteen feet, potential forest trees like magnolia, twin live-oak, and laurel-oak are very little higher. In general the maximum height is fifteen to twenty feet. On the one hand, woody plants ordinarily small tend to grow up toward the maximum stream-lined level; and on the other, those commonly larger are prevented from growing higher than the same maximum established by the wind. In other words, the top of the vegetational canopy is far more nearly a straight line than the ground profile across the ridges. From five to ten miles farther north, the same magnolia, twin live-oak, and laurel-oak strike heights of forty, fifty, and sixty


Plate 9.Three scrub types, east coast and interior.


feet in the hammock behind the dominant dune ridge. A few miles south of the profile under consideration the hinterland is also characterized by large trees. In this hammock the soil is black and locally enriched by shell mound material. The hammock farther to the north with the sandy soil rich in humus showed no such substratum. What conditions determine locally the low woody growth instead of a tall hammock as found to the north or the south was not obvious to the writer at the time of the field observations.
A few successional tendencies stand out. Laurel-oak is not a co-pioneer of twin live-oak and scrub-oak. It comes in later, holding to the higher places; whereas twin live-oak shows little choice in the slightly different elevations found here. Of interest, too, is the fact that twin live-oak and saw-palmetto are found from the foredune throughout the whole series, while tough-buckthorn and shore-bay fade out in the hinterland. As usual, stagger-bush {Xolisma ferruginea), blueberry, and sparkleberry are correlated to the older sands running acid. The higher dune ridge at the front was all fine sand, but in the lower strata even farther back considerable shell material indicated a soil too rich for spruce-pine. This species, nearly always on the poor white Pleistocene sands west of the coastal lagoons, is usually absent on the more recent shell-rich dunes of the barrier-islands of the same latitude. However, modern dune sands well bleached as at Daytona Beach and other points nearly always display the spruce-pine.
Plant List
Sea-oats zone
Cakile edentula Sea-rocket f
Ipomoea Pes-Caprae Railroad-vine
Uniola paniculata Sea-oat
Croton punctatus Silver-leaf croton
Three scrub types, east coast and interior. Top: palmetto-oak scrub. Recent dunes about 10 miles north of Vilano Beach, St. Johns County. Middle: typical oak-spruce-pine scrub with saw-palmetto in Ocala National Forest. Twin live-oak, scrub-oak, Chapman's-oak, saw palmetto, although black-jack oak, scrub-palmetto and silk-buckthorn, scrub-bay, Stagger-bush (Xolisma ferruginea), and others are found here. Bottom: young spruce-pine thicket. As many as 100 or more saplings or small trees may be counted in 25 square feet. Saw-palmetto extreme left and rosemary, front center. Ocala National Forest.
Yucca aloifolia Raimannia humifusa
Spanish dagger Seaside evening-primrose
f Generic common names.
EXPLANATION OF PLATE 9.


'/.::/. ':".* '.--V..VpH' 75,8V
...... ........ i r jiii
Serennn repens
Cakile edeotulo Untold paniculata_
Tamnla /ittorn/is
Rum el in fenny
Magnolia grondlffora
Quercus qeminnta
Cprgthamnus ceriferus
nne.-tiiK laurifntia
Xolisma ferruginea
Magnolia_grandiflora
iqgnoua_gi__
Tamnla_littarafis
Quercus lourifolia
Xolisma ferruginea
Quercus geminqta
Cerothamnus ceriferus
Serenoa repens
Baccharis halimifolia
Rntndfindron nrhnreum
Plate 10.-Vila.no Beach, profile.


Salsola Kali Sporobolus virginicus Chamaesyce Ingallsii Helianthus debilis Cirsium horridulum Erigeron pulcJielhis
Saltwort Rush-grass t Spurge t Sunflower t Yellow-thistle Robin's-plantain
Scrub zone
Serenoa repens Bumelia tenax Ilex vomitoria Tamala littoralis Quercus geminata Amarolea americana Quercus myrtifolia Oerothamnus ceriferus Magnolia grandiflora Quercus laurifolia Xolisma ferruginea Smilax auriculata Batodendron arboreum Baccharis halimifolia Bivonea stimulosa Pteris latiuscula Desv. Erigeron pulchellus Ceratiola ericoides
Saw-palmetto
Tough-buckthorn
Yaupon
Shore-bay
Twin live-oak
Wild-olive t
Scrub-oak
Wax-myrtle
Magnolia t
Laurel-oak
Stagger-bush
Wild-bamboo
Sparkleberry
Groundsel-tree
Spurge-nettle
Bracken
Robin's-plantain
Rosemary
PONTE VEDRA
This five-mile study represents a strip beginning about three miles south of Ponte Vedra and ending about eight miles farther south. Here are found great extremes of habitat and plant associations condensed into a small cross section. From the violence seen in windsweeps and eroding slopes of the dunes at the ocean front, it is only a quarter mile to the tranquility and luxuriance of the inland hammock or fresh water lagoon. The wave erosion and sand dune migration witnessed at the Vilano Beach section farther south is here seen on a magnified scale. In places the slumping sand cliff runs upward for twenty-five feet at an incline of about 35. Protected by only a low narrow foredune, the slope shows the havoc of high tide by the dead cabbage-palms that stick to the slope in haphazard positions. An erect palm can make no adjustment to a sandy substratum that falls away from its roots.
Saw-palmetto and Cabbage-palm
Saw-palmettoes, though, with their rhizomes clinging close to the surface can adapt themselves slowly to changing conditions like accumulation or removal of sand. On the eroding cliffs, however, the writer observed saw-palmettoes dead because of exposure, but heading upward on the slope. The production
t Generic common names.
t Departure from Small's manual, as to common name.


Figure 7.Shoreline encroachment, foredunes, and blow-outs, Ponte Vedra, St. Johns County. Dunes at Ponte Vedra showing wave action or encroachment on low foredunes, shifting inwardland of eroded sand and irregularity of main dune ridge because of blow-outs. Vegetation: foreground, saltgrass; on rounded dune just behind Iva; and behind the latter abundant sea-oat; cabbage-palm on top of ridge; and seaweeds washed up on beach.
Although the plants are there, one seldom sees a palmetto germinate in high and dry sand. It is likely that many of these high and dry palmettoes establish themselves in low wet pockets and then vegetate upward with the dune. Cabbage-palms, however, may be seen germinating almost anywhere in the vicinity of parent plants. Consequently, when it comes to occupying
of new root and stem growth to follow the receding slope had been too slow to anchor them to sliding sand. The skeletons, free and poised away from the seaward incline, told the story. Where the movement of the sand was not too swift saw-palmettoes were holding on and growing upward toward stability. Slow horizontal advance makes palmetto of no value in gaining or capturing ground where there is appreciable sand movement; but palmettoes can and do grow straight up when sand accumulates upward around them. Here again because of sluggish elongation sand often overtakes and buries them. In short, wherever sand is in motion, palmettoes persist or hang on in spite, not because, of the disturbance.


florida dunes and scrub
63
new areas too dry for seed germination, palmettoes mostly take it slowly, if at all, by vegetational advance of rhizomes; and immobile cabbage-palms establish themselves there by disseminated seeds. Ample evidence of germination and establishment in all of these settings can be found; so that establishment of the cabbage-palm does not seem to be critical.
The method of establishment of the plant, however, is of extraordinary interest. In the first stages of development from the seed, the plant sends its stem downward Most plants with erect stems, as is well-known, send their root or root systems downward. But the cabbage-palm in its early stages of development forces its stem downward to a depth in some cases at least
Figure 8.Stages to show a cabbage-palm stem anchors plant: first, stem anchors plant, makes a hair-pin turn, reverses its direction and finally emerges as an erect stem with a crown of leaves at the tip.
four feet. Curiously enough as the stem descends, it becomes increasingly larger in diameter so that the subterranean stem looks like a club with the deepest end rounded into a smooth knob, or knee. As this downward development proceeds, more and more adventitious roots follow progressively from behind. How this thickened butt end of a stem can force its way down against the packed sand is indeed puzzling. Every year in this downward growth the continually enlarging stem sends up a new set of leaves. These leaves emerge upward through the sand closely hugging the stem in their climb to the surface. In going down the stem exhibits a positive geotropism, growth or


movement toward gravity; but there comes a time when the stem tip becomes negatively geotropic and makes a sharp hairpin turn, reverses its direction, and grows upward as most stems do. With every year there follows an increase in diameter so that by the time the butt of the buried stem has definitely emerged, the palm stem will have reached or nearly reached its maximum diameter. In other words, after the emergence above the soil there is not much increase in the diameter of the stem.
Figure 9.Ascending saw-palmetto in Ponte Vedra hammock. A very moist shady hammock characterized by robust spreading live-oaks, magnolias, cabbage-palms, and an understory of luxuriant, sometimes semi-erect, saw palmettoes. Five miles south of Ponte Vedra, St. Johns County.
Ordinarily palmetto creeps just above or below the surface; but, supported or chased by sand accumulation, it will grow straight up. Subsequent removal of the sand may leave the plants standing like awkward trees. In the hammock behind, where shade is intense and humidity great, palmetto rhizomes usually grow on the surface, but often ascending rhizomes lift their rosettes of leaves five or ten feet above the ground.
The cabbage-palm, although able to start almost anywhere, cannot withstand burial by the sand. Unlike the saw-palmetto it cannot escape from covering sand by means of a creeping rhizome and development of adventitious roots along that rhizome. Cabbage-palm may start as a seedling in a hammock,


drive its tops as high or higher than a magnolia, but it is easily killed by burial of sand brought in from an invading dune. In the lee of a huge blow-out at the Ponte Vedra section stand a number of dead headless palms like so many posts driven into the sand. Saw-palmettoes cannot lift their leaves above a few feet except in a few cases as already noted in the case of weak rhizomes which sometimes make a feeble attempt to carry the crown upward. The saw-palmetto, however, can run away from a blow-out dune if not too severe, or from covering sand if not too rapid, by means of a creeping or sprawling rhizome. Cabbage-palms cannot run at all.
Despite certain short-comings of both species they have a remarkable range in the dunes. The saw-palmetto soon appears as an isolated clump in the low hollows of foredune ridges. Once established, unless conditions become too severe, the plant hangs on, to the point of domination in palmetto-scrub
Figure 10.Cabbage-palms in shallow lagoon south of Ponte Vedra, St. Johns County. This scene shows cabbage-palms growing on the edge of the lagoon which borders the rear dune south of Ponte Vedra, St. Johns County. See a cabbage-palm in contrasting dry sandy habitat in figure 16.
association, throughout the dune series and into the hammock. As far as dunes or scrub go, the only limiting factor seems to be a surplus of water. Saw-palmetto drops out in shallow standing waters of lagoons where red maples, dahoon hollies,


Virginia-willow, wax myrtle, and other woody plants, especially cabbage-palms flourish.
The cabbage-palm, a strikingly versatile plant, thrives anywhere from the foredunes throughout the hammock, and on into the forested lagoon. As a matter of fact, the palm is found in almost any kind of habitat: old fields, wet prairies, flatwoods, lagoons, hammocksalmost anywhere. With roots in water or in sand only slightly moist, in open prairie or dense ham-
Figure 11.Blow-out dune invading cabbage-palms. Jacksonville Beach, Duval County. From Cooke, Scenery of Florida, Fla. Geol. Surv. Bull. 17, 1939.
mock it towers with or over powerful competitors. In the crowded oak-magnolia hammock at Ponte Vedra, it holds its own against strong trees like magnolias. Cabbage-palm trees of all sizes and ages are to be found there although they favor the lower areas, whereas magnolia holds to the knolls or ridges. In one instance a palm shot upward close to a magnolia trunk scathing the leaves, twigs and bark by its tough whipping leaves. Since the columnar palm makes no lateral branches the magnolia was left free to force many new branches induced by wounds the palm left on the trunk as it brushed its way upward against the magnolia.
Blow-outs
Pronounced scenic features are the blow-outs, so well developed in the vicinity of Ponte Vedra. Their steep-sided fronts coming on, spilling and filling nooks and hollows of forest with


choking sand, make an impressive sight. Equally spectacular are the gigantic barren troughs or channels of the ocean side. The scouring and incessant marching of sand makes foothold for plants ^difficult and precarious on the weather side; while on the leeward slope the sand instability and smothering preclude or destroy many plants. The windward slope runs up at a low angle of 10 to 15, or thereabouts; the lee may be as steep as 35 approximate angle of rest for the sand. By special adaptations a limited number of plants can survive in such an avalanche.
The twin live-oak, able to survive slow burial by virtue of roots sent out from younger stems, perishes if sand suddenly covers the older trunks for a number of feet. These older trunks are unable to produce a new adventitious root system to carry on the function of the deeper roots which are suffocated by the sand cover. As a result a large live-oak, suddenly overtaken by sand deposits, ceases to live. If the burial is slow and begins early in the life of the oak when the branches are still small, the oak will send out subterranean running stems which emerge vertically as new shoots. These shoots by indefinite branching and production of roots may, in reaction to sand covering, spread and grow indefinitely and form a large complexity of partly buried, partly exposed shrub or thicket.53 Detachment of any surviving part makes a new plant. The ability to produce adventitious roots is characteristic of all the woody plants that are able to survive or multiply in an avalanche of burying sands.54 Magnolia, twin live-oak, saw-palmetto, French-mulbery, yaupon, and muscadine grape are such species. Observations made in the pursuance of the present work make it possible to add scrub-oak, Chapman's-oak, tough-buckthorn, shore-bay, and red-bay as other woody species that respond to sand burial with adventitious roots. And thus there is in part the explanation of spreading thicket formation and its ability to modify sand movement. It is, however, very necessary to emphasize that most of these plants tend to the same spreading habit and method even in sterile and sundrenched sands of quiescent dune or scrub. In a shady forest of good soil, species like scrub-oak, twin live-oak, and Chap-
53 Kurz, Herman, The reaction of magnolia, scrub live-oak, slash-pine, palmetto and other plants to dune activity on the western Florida coast: Proceedings of the Florida Academy of Sciences, p. 201, 1939.
54 Ibid., p. 202.


man's-oak tend to have a single stem or trunk. A woody plant that branches below the ground is a shrub and one that branches above is a tree. It follows that, according to the environment, the same species may be tree or shrub.
On some of the lee slope where light conditions permit and movement is not too violent, some perennial herbs like seaside-pennywort creep down the slope from above. Perennial colonies of the semi-shrubbery silver-leaf croton, or horse-mint may also move downward; and so may isolated plants of spider-wort and yellow thistle, or the purple variety. But mostly the sand is so unstable, the light so weak as to exclude herbs from the leeward sides of blow-outs advancing on a hammock or a colony of pioneer dune trees and shrubs like twin live-oak, scrub-oak, shore-bay, tough-buckthorn, and yaupon.
Figure 12.Undermined cabbage-palm. Shore encroachment killing cabbage-palms five miles south of Ponte Vedra. Young Spanish dagger plants to left.
Because of increased wind velocity and fast movement of sand, the windward sides of blow-outs offer slight foothold to vegetation; consequently, absence of obstructing plants along with concentrated wind and copious sand make blow-outs the highest and most spectacular dunes of the coast. Along the east coast of Florida the elevation of relatively stable dunes
* After Penfound and O'Neill.


seldom exceeds twenty-five feet; it is often less; however, the blow-outs south of Ponte Vedra reach thirty, possibly forty feet. Cressey 55 considers the advent of the white man with all his activities an important agent in initiating blow-outs. No doubt some of the windsweeps of Florida have had their inception hastened by players along the shore. But of certain importance is an invading shoreline in clear evidence between St. Augustine and Mineral City. Near Mineral City where Martens 56 calls attention to the many blow-outs, shore invasion has progressed to the point of considerable destruction of the main dune ridge. A steep cliff punctuated by raggedness produced by blow-out characterizes now what was once a regular dune ridge. Dune destruction by blow-outs is often accompanied by reversed positions of plants. Species ordinarily in the back
Figure 13Ponte Vedra dune hammock with magnolia in lee of blowout. Magnolia, live-oak, cabbage-palm hammock in the lee of advancing blow-out dune at Ponte Vedra, St. Johns County. Note lush and stately appearance of magnolia as contrasting to scrub magnolia shown on Panama City Beach blow-out.
must now succumb to winds and waves of eroding shore; while those usually on foredunes may now venture far back and up the slope where unstable sands favor their establishments. Thus, live-oaks and palms of long standing may fall down the
Cressey, George Babcock, The Indiana sand dunes, p. 42. Martens, James H. C, Beaches of Florida, pp. 98 and 100.


eroding slope; and Iva and Croton and sea-oats of foredunes grow high up and far inland on a blow-out dune. It seems obvious that an invading shoreline must necessarily favor inception and development of blow-outs; for it shortens the distance between beach and foredunes so that the waves and onshore winds straight from the ocean and with little obstruction in their path can operate with greater force. Tumbling palms at the cliff, exposure of roots (fig. 12) and plants in the windward channels, massive sand lumbering over trees at the lee, drifting sand on the highwayall testify to concomitant encroachment of sea and sand.
Behind the advancing blow-outs lies the hammock of live-oak, twin live-oak, laurel-oak, magnolia, and cabbage-palm. Of the oaks, live-oak is the largest, reaching up to fifty or sixty feet.
In general, the writer has found, that where sands have an original abundance of shell fragments, a condition being true here, the common live-oak predominates over the twin live-oak. On the other hand, twin live-oak, although found along this stretch, especially in the open exposed and shell spots replaces live-oak entirely in dune hammocks with acid soils predominating in quartz and devoid of basic shell material. At Cape Canaveral, where shells are abundant, was found what Small has described as Rolfs'-oak.57
Here and there are groves of magnolia having ten and twelve inch trunks with a mixture of live-oak, threatened by the march of advancing blow-out. In other localities the smothering is in progress and live-oaks and magnolias are responding with stunted, spreading growth. Still other places display exposed, straggling, barely living forms perched on turret-like sand mounds."8 These growth forms represent trees, at one time normal, but now caught and distorted by mounting sand and wind. Continued advance of the blow-out on and beyond these trees is resurrecting them from living burial. In reality they are not perched on the sand: it is rather their closely massed stems and roots that hold these islands of sand in the blow-out complex/'11
57 To the writer it appears that Rolfs'-oak is no more than a geographic or environmental form of live-oak. Variations of leaves and acorns are extreme in Rolfs'-oak but very similar to live-oak. The sand dune environment induces great leaf variations in Rolfs'-oak; but even so just about as many forms and quite the same types fall also from the top of a large inland live-oak tree.
53 Cressey, George Babcock, op. cit., p. 35.
Kurz, Herman, The reaction of plants to dune activity, p. 197.


uaKiie eaentuia Ipomoea Pes Caprae Spartina patens
/tea virginica
Serenoa repens
_ Uniola pan/golata
Hvdrocotyle bonariensis
Ipomoeastolon if era
Ivn imhricatrt
_Croton punctatus_
Yucca alaifaha Smtlax aurtcutata
Sabal Palmetto
Tamala littoralis
Rumelia tenax Quercus gem/nata_
Hex vam i tor in
Amarolea americana
Onerous myrtifo/ia
_. Aralia spinas
Magnolia grandi flora
unosa
nalficarpa americana
Sabina siticicola
Ilex opaca s2l
Cemthamnus ceriferus
vercus._virgtmana
Desmothamnus tucidus Xolisnja ferruginea
Ilex Cass/ne
Plate 11.Ponte Vedra profile.


Plant List
Sea-oats zone
Cakile edentula
Ipomoea Pes-Caprae
Iva imbricata
Spartina patens
Uniola paniculata
Hydrocotyle bonariensis
Ipomoea stolonifera
Croton punctatus
Yucca aloifolia
Capriola Dactylon
Cirsium horridulum
Cirsium horridulum Elliotii
Chamaesyce Ingallsii
Raimannia humifusa
Tradescantia foliosa
Sporobolus virginicus
Monarda punctata Scrub zone
Smilax auriculata
Serenoa repens
Sabal Palmetto
Bumelia tenax
Quercus geminata
Tamdla littoralis
Ilex vomitoria
Quercus myrti folia
Amarolea americana
Baccharis halimifolia
Quercus Chapmanii Hammock
Gallicarpa americana Aralia spinosa Magnolia grandiflora Sabina silicicola Cerothamnus ceriferns Ilex opaca Quercus virginiana Desmothamnus lucidus Tamala Borbonia Zanthoxylum Clava-Hercults Smilax Bona-Nox Muscadinia rotundifolia Xolisma ferruginea Quercus laurifolia Quercus Rolfsii Parthenocissus quinquefolia Toxicodendron radicans Laurocerasus caroliniana Elephantopus tomentosus Eupatorium aromaticum Wet hammock zone Hex Cassine Itea virginica Sabal Palmetto Rufacer carolinianum Osmunda regalis L. **
Sea-rocket f Railroad-vine Marsh-elder t Salt-grass Sea-oat
Sea-side-pennywort Morning-glory f Silver-leaf croton Spanish-dagger Bermuda-grass Yellow-thistle Purple-thistle Creeping-spurge Seaside evening-primrose Spiderwort t Rush-grass f Horse-mint t
Wild-bamboo
Saw-palmetto
Cabbage-palm
Tough-buckthorn
Twin live-oak
Shore-bay
Yaupon
Scrub-oak
Wild-olive f
Groundsel-tree
Chapman's-oak
French-mulberry
Prickly-ash
Magnolia $
Southern red-cedar
Wax-myrtle
Holly
Live-oak
Fetter-bush
Red-bay
Toothache-tree
Bamboo
Muscadine grape
Stagger-bush J
Laurel-oak
Rolfs'-oak
Virginia-creeper
Poison-ivy
Mock-orange, cherry-laurel t Elephant-foot f Wild-hoarhound
Dahoon
Virginia-willow Cabbage-palm Carolina-maple Royal fern
t Generic common names. After Penfound and O'Neill. ** Small, J. K., Ferns of the southeastern states (1938). t Departure from Small's manual, as to common name.


ST. JOHNS BLUFF
Facing the St. Johns River valley at Fort Caroline, St. Johns Bluff extends southeastward for about a mile. At the foot the bluff reaches eighty or ninety feet. The bluff itself as well as the undulating sand hills of this section represents fossil dunes of Pleistocene times.60 The road leading to the fort cuts through old dunes long since developed into a sandy hammock of twin live-oak, magnolia, and other hardwood species; about one-half mile from where the road turns to go to the fort one part continues straight northeastward over the seventy-foot high ridge extension of St. Johns Bluff, down the steep northeast facing slope, and on across the low irregular sand hills and depressions lying to the northeast of the ridge. The last named irregular hill region and the ridge itself, both covered with dune scrub, and the hammock southwest of, but adjacent to, the ridge are all characterized by the same acid quartz sands of Pleistocene dunes. The study of the profile presented parallels the road from low hills of the northeast, across the ridge, and to the hammock of the southwest.
Figure 14."View from the ancient dunes at St. Johns Bluff, Duval County, across the marshes to St. Johns River." From Cooke, Scenery of Florida, Fla. Geol. Surv. Bull. 17, 1939.
bo Cooke, C. Wythe, Scenery of Florida, p. 54; and Leverett, Frank, The Pensacola terrace, p. 14.
3-A


74 florida geological surveybulletin twenty-three
Scrub and Climax Forest
In spite of the identical origin, similar sands, and similar acidity there is a striking contrast in vegetation which exposure alone can explain. In the low sands at the northeast is typical scrub of varying height and luxuriance depending on local elevation. Where the land lies low and even, flatwoods vegetation with slash-pine (Pinus palustris) is evident. Even in the depressed pockets of the gentle hills grows considerable slash-pine. But now go south westward up the 20 incline of the ridge, and notice the tall scrub of the lowland becoming shorter with a trimmed neatness that clearly indicates the cutting effect of prevailing winds as they sweep across the lowlands from the east and hit the ridge broadside. The ridge drops at about a 15 angle to the west; the same species, stunted on the east-face, now on the west become taller and taller on the way down the hill. Accordingly, the contour appears a level canopy stretched from the thicket at the crest to the forest top farther back and does not at all follow the sharp dip in the land from hill to lower land. Species like twin live-oak, scrub-oak, Chap-man's-oak, and saw-palmetto, all stunted on the east attain progressively higher stature to the west. Scrub-oak and Chapman's-oak finally drop out, but twin live-oak stays on and becomes the largest and most abundant tree of the hammock. Stagger-bush (Xolisma ferruginea) and wild-olive, scrubby on the ridge, reach heights of twenty feet. A number of other forest trees typical of the hammock, like magnolia, laurel-oak, pignut, with holly and flowering dogwood as understory trees, are also here. Shore-bay of the scrub is in the hammock replaced by red-bay with a few of the former hanging on. Saw-palmetto of the open scrub is in the forest much taller and deeper green. The presence of young magnolias are destined to play a more dominant role in the future. Exploitation of the magnolias for their foliage and other uses has for the present reduced their number and dominance. We have, therefore, no accurate picture of how dominant the magnolia would be if a hammock of this type were unmolested for two or three hundred years. However, in the Ponte Vedra hammock the writer saw live-oaks leaning away from a central magnolia; on the other hand, a live-oak caught between two magnolias stretched itself skyward in a tall squeezed outline. Behaviors of this kind point to the fact that magnolia leaves can stand more shade than live-oak. It is not uncommon to find a young


magnolia thriving in the shade of large live-oaks, sometimes directly under the spreading limbs, poking its shoot straight upward through the maze of branches. But in the dense shade of magnolia groves, one seldom sees young trees of any kind not even magnolias. In a forest where only nature rules, the most shade enduring species is the ultimate species of the climax forest.
Evidence like the foregoing picked up from pitiable remnants of former virgin hammocks along the east coast points to the conclusion that if natural processes alone rule in vege-tational development the goal is a magnolia climax, magnolia being at least locally the final tree with live-oak, pignut, laurel-oak, holly, and various understory trees, shrubs, and saw-palmetto playing subordinate parts in varying degrees. This generalization holds for the older stages of the forested dune series where moisture relations of the soil are moderate. In the dune hammocks as at Ponte Vedra the picture of the climax forest is complicated by the fact that the cabbage-palm offers strong competition to th^ magnolia especially in "the wetter soils. Observations in general lend some support to Marten's assertion that the cabbage-palm seems to shun highly siliceous sands.61 The writer has not worked out the details of the complication, for it is in the forest soils of medium water relations and high siliceous sand content that cabbage-palm often falls out but not always. It is true, however, that in well-drained sandy dune soils, rich in humus, magnolia is often unchallenged by the cabbage palm.
Plant List
Scrub zone
Pinus palustris < Slash-pine
Ceratiola ericoides Rosemary
Ximenia americana Tallow-wood
Quercus myrtifolia Scrub-oak
Cyanococcus Myrsinites Blueberry f
Smilax auriculata Wild-bamboo
Quercus Chapmanii Chapman's-oak
Tamala littoralis Shore-bay
Serenoa repens Saw-palmetto
si Martens, James H. C, Beaches of Florida, p. 109.
62 By personal communication, Erdman West, Director of the Herbarium, Agricultural Experiment Station of University of Florida, and Wilbur B. DeVall, University of Florida Forestry Department, consider all slash-pines north of Daytona Beach on the east coast and north of Tampa on the West Coast as Pinus palustris Mill.
t Generic common names.


Yimenin rimer icnnn
Otmrnus myrtifnlin
Cyanncapcus Myrsinites
Smt'/ax_auriculata
Quercus Chapman ii
Tama la tittnrat7?
Serenna repens
Amnmlea_americana
Xntismn ferruqinea
Querent_gem ma fa
RntnHenrlrnn nrhnreitm
Quercus_(attrifaUa
Mnnnntin_grandiftara
M
Tcorio glabra
Mitchell a repens
Ilex apnea
Smilax pumita
Aralia soinosa
Symplocs tinctoria
Tama I a Rarhonia
Ha ma metis virg Cynoxylon floridum
virgin tana
Plate 12.St. Johns Bluff profile.


PLANT LIST (continued)
Amarolea americana Xolisma ferruginea Quercus geminata Batodendron arboreum
Wild-olive Stagger-bush f Twin live-oak Sparkleberry
Hammock zone
Quercus laurifolia Magnolia grandiftora Hicoria glabra Mitchella repens Jlex opaca Smilax pumila Aralia spinosa Symplocos tinctoria Tamala Borbonia Hamamelis virglniana Cynoxylon floridum
Laurel-oak Magnolia J Pignut Twin-berry Holly
Sarsaparilla-vine
Prickly-ash
Sweetleaf
Red-bay
Witch-hazel
Flowering dogwood
NORTHWEST GULF COAST DUNES
COCHRAN'S BEACH
From the vicinity of the Ochlockonee River south of southeast to the Anclote Keys, there is very little beach or dune development in direct contrast to the east coast or the gulf coast west of here. A number of writers comment on the paucity of sandy beach and the presence of coastal marshes instead.63 The condition seems related to a number of conjoined factors: shallow or gently sloping offshore bottom acting as a barrier beach reduces the effectiveness of waves to carry sand or to beat against the shore; winds perhaps somewhat weaker along the gulf coast than on the Atlantic may also play a part in the diminished action; there is also a scarcity of sand for the clear streams entering this part of the coast traverse limestone areas from whence they bring little sand load.64 Another factor negating any considerable sand supply in this section of the coast may lie in the fact that there are no prevailing long-shore currents as there are on the east coast to bring the sand from the north or elsewhere.6"' For the section farther west, however, Sellards states:
"The western part of the gulf coast from Franklin to Escambia County is a section from which limestones are absent and sandy clay formations are exposed. Along this coast the sand dunes are again found more or less continuously."
t Generic common names.
% Departure from Small's manual, as to common name.
63 Harper, Roland M., Geography of central Florida, pp. 88 and 164.
64 Sellards, E. H., The soils of Florida, p. 74, and Cooke, C. Wythe, Scenery of Florida, p. 60.
65 Cooke, C. Wythe, Scenery of Florida, p. 60; and Martens, James H. C, Beaches of Florida, p. 105.


go Martens, James H. C, Beaches of Florida, pp. 111-112; and Cooke, C. Wythe, Scenery of Florida, p. 76.
g? Martens, James H. C, Beaches of Florida, p. 109.
Streams cutting across these sandy clay formations bring sand and silt into the gulf. Prom the Ochlockonee River westward are excellent beaches and dunesrecent and active or ancient and quiescent, all veneered with dazzling white sands.
Cochran's Beach, the object of the first study, lies near St. Teresa on St. James Island, Franklin County. The technical "island" is really a piece of the mainland, the Crooked and Ochlockonee Rivers encircling it from behind. At this locality the beach is exposed to direct winds and waves of the gulf, but a shallow reef between Dog Island and Alligator Point (Peninsula Point) reduces the activity at the coast line.
Shore Erosion
Stumps of dead pines, still in the place where salt water killed them and vegetation commonly of the hinterland growing on the edge of the water bear testimony to the fact that the shoreline is advancing on the mainland.60 Martens 67 has noted that the sand is much more siliceous on the northwest coast than in other beaches of Florida; he also suggests that this may in part explain the difference between the vegetation of the northwest gulf coast and other parts of Florida. That seems true: there is a notable similarity between the vegetation of Cochran's Beach dunes and that of the stable back dunes at Daytona Beach. Both situations are marked by highly leached sands. Even the St. Johns Bluff vegetation and sand has its counterpart on old quiescent dunes at Lanark or Carrabelle, respectively ten and fifteen miles farther west from Cochran's Beach. In fact the species found at Daytona Beach or at St. Johns Bluff can, with few exceptions, be duplicated in a number of dune localities from Lanark to Pensacola. Conversely, the southern red-cedar, so abundant on the alkaline dunes of coquina origin in the vicinity of St. Augustine, is not a regular feature of the northwest gulf coast. Also, as has been similarly noted by Martens, the cabbage-palm so common on the east coast is little seen on leached dune sand of the eastern part and not at all in the western section of the north gulf coast dunes. It is, however, fairly common on low dunes in the vicinity of


Indian Pass. The writer has no explanation for this behavior of the palm. Another observation indicating the importance of calcareous or siliceous sands in plant distribution may be here reiterated. The scrub species so prevalent in these northwest gulf coast dunes also grow far south at Jupiter and Cape Canaveral, but they restrict themselves to the acid siliceous sands of those regionsnot to the basic or calcareous ones. As indicated previously in discussing the Jupiter profile, distribution is not all a matter of latitude or climate.
Figure 15.Eroding shore of St. George Sound two miles east of Apa-lachicola Bay bridge. Stumps and dead roots in salt water. From Cooke, Scenery of Florjda, Fla. Geol. Surv. Bull. 17, 1939._____
In dunes that are building, the spruce-pine is usually a considerable distance in the back where the sand is leached and stabilization rules; at Cochran's Beach, however, it stands just behind or at the very front of oncoming blow-out dunes. The interpretation is that this is not so much a case of the spruce-pine placing itself so near as it is that the shoreline and driving dune are threatening the occupancy of the pine. As a matter of fact, young spruce-pine, black-jack and turkey-oak are establishing themselves on low foredunessomething the author has not seen elsewhere. Indeed, black-jack and turkey-oak, normally, high pine land trees, are a rarity on any recent dunes. They are often found, however, in the hinterland where dune scrub goes into high pine land. Along the west coast such mergers, gradual or abrupt, of dune scrub into black-jack and


long-leaf pine are common even where there are no perceptible changes in topography. About the only obvious difference to be seen is the white surface soils of scrub and the darker gray or buff top-soil of the black-jack. Other differences will be noted in the section of this report on scrub. It may be that the beach and low foredunes of the present invading coast line represent in part a reworked mixture of sands of the hinterland which were once suitable land for black-jack, turkey-oak, and spruce-pine and which are now again suitable. This admitted
Figure 16.-"Shore of Inlet Lake, near boundary of Bay and Walton Counties. Bluff cut by storm waves in sandy land with scrub vegetation. The shore is sandy but has a narow strip of marsh vegetation, because a sand bar, faintly seen in the distance at the left of the picture, shuts off the waves from the gulf during all except the most severe storms." From Martens, Beaches of Florida, Fla. Geol. Surv., Twenty-firstTwenty-second Ann. Rept., 1931.
speculation is easier to apply to the spruce-pine, a common species in dune development, than to the oaks seldom seen in recent dune systems.
Though not as spectacular as dead stumps in salt water, another evidence of an invading shore is observable at Cochran's Beach: by digging up rhizomes of sea-oat which reached seaward from higher beach levels, the writer consistently found dead tips or ends down at the lower levels of salt water saturation. In further consideration of shoreline encroachment, the writer calls attention to Marten's observation in connection


with his figure of Inlet Lake near the boundary of Bay and Walton Counties. Dog Island, too, is characterized by eroded sand bluffs with perished trees slumping down the steep slope. The large skeletons represent an age and stability of dune and vegetation that they could only have attained when the surf was much farther out in the gulfpossibly several hundred feet.
Behind the narrow belt of telescoped dunes of Cochrane Beach and within one thousand feet of the salt water lies a flatwoodsdune mixture of species representing the two types of plant habitats.
Figure 17."Pine tree stump and top roots protruding through beach sand, showing that land has been here recently and worn away by the sea. Dog Island, Franklin County." From Martens, Beaches of Florida, Fla. Gecl, Surv., Twenty-firstTwenty-second Ann. Rept., 1931.
Plant List
Sea-oats zone
Uniola paniculata Raimannia humifttsa Salsola Kali Hydrocotyle bonariensis Panicum portoricense Rumex hastatulus Fimbristylis castanea Cakile edentula Tradescantia foliosa
* After Penfound and O'Neil. t Generic common names.
Sea-oat
Seaside evening-primrose Saltwort
Sea-side-pennywort Panic-grass f Dock t Sand-rush Sea-rocket t Spiderwort f


PLANT LIST (continued)
Spruce-pine zone Quercus laevis Quercus cinerea Ilex vomitoria Quercus geminata Pinus clausa Ceratiola ericoides Serenoa repens Pinus palustris Quercus myrtifolia Clinopodium coccineum Amarolea americana Quercus Chapmanii
Black-jack % Turkey-oak Yaupon Twin live-oak Spruce-pine Rosemary Saw-palmetto Slash-pine Scrub-oak Basil t Wild-olive t Chapman's oak
Flatwood zone
Cerothamnus ceriferus Aristida stricta Cyanococcus Myrsinites Xolisma fruticosa Xolisma ferruginea Desmothamnus lucidus Pinus australis
Wax-myrtle Wire-grass Blueberry t
Stagger-bush t Stagger-bush t Fetter-bush Long-leaf pine
CLIMAX FORESTS OF LANARK AND CARRABELLE
At Lanark the ancient dunes, attaining elevation of twenty-five or thirty-five feet, are covered by sandy hammock or hardwood forest species that have succeeded spruce-pine associations of long ago. At Carrabelle commoner forest trees were: twin live-oak, pignut, magnolia, holly, with here and there a relic spruce-pine and rosemary, hanging on from the previous stage, and undergrowth shrubs of stagger-bush (Xolisma ferruginea) > fetter-bush, and sparkleberry. Since the field observations this forest has succumbed to the ax. At Lanark, although somewhat disturbed by the presence of modest summer cottages or houses, there is still a grove of trees that gives a fair picture of a magnolia climax forest as developed on old dunes of the northwest coast. This magnolia forest was so striking that the author examined the soil to make sure it represented dune sand. The top-soil is leached sand grayed by humus; the next eighteen inches is creamy white and below that yellow or orange. The dominant tree is magnolia. One patch is about fifty by one hundred feet contains twelve trees with a diameter of four to fifteen inches breast high, but there is no undergrowth except abundant yaupon, small-fruited paw-paw, and French-mulberry. Mixed with the magnolia trees is one pignut of fifteen-inch
j Generic common names.
t Departure from Small's manual, as to common name. After Penfound and O'Neil.


00 co
Uniola paniculate
SalsolQ_ Kali
Raimnnnin humifti^g
Hydracotyie hanarie.nsis
Galium hermudense Qitarn/c //7pi//>_
if ex vomitoria-
Ouercus geminata
Pin us clausa
Ceratioia_ erica ides
Serenoa repens
Pi mis palustris
Quercus myrtifolia
Clinopodium coccinum
QimrniKi_C.hnpmnnii
Cerothamnus. cpriferus.
Aristirin striata r.yrtnnnnnr.us. MytSinites
Xolism a fruticqsg tn
Desmothamn_m_lt_uZu
Plate 13.Cochran's Beach profile


Figure 18.Magnolia climax on old dune at Lanark, Franklin County. Compare single-trunked sturdy magnolia trees with the scrub magnolias shown in Panama City Beach blow-out (Plate 7). Note also absence of understory vegetation so characteristic of magnolia climax forest.
The writer saw no young trees under the mature magnolias, but he did see half a dozen ranging from six to eight feet high growing under the oaks on the edges of the magnolia climax. This is quite in agreement with observations made on other magnolia forests or remnants along the east coast, nortwest coast and even interior northern Florida. Up to the present the author has not noticed a magnolia of less thftn inches in diameter or 35 feet in height growing under a den^e canopy formed by a pure stand of mature magnolias; but he has often seen them coming up in the shade of mixed hardwoods forest, even growing straight up through the shady maze of live-oak limbs. Even in the local clearings of Magnolia forests, made by storm or man, it is species like Walter's pine (Pinus glabra), short-leaf pine (P. echinata), loblolly pine (P. Taeda)y sweet gum (Liquidambar styraciflua), silver bell (Halesia diptera), pignut hickory (Hicoria glabra),;, and redbud (Cercis Canaden-
diameter and one red-bay of eight-inch diameter. Here and there are twin live-oak, laurel-oak, holly, with scrub-oak, Chap-man's-oak, and spruce-pine on the periphery.


sis), not young magnolias, that first fill the gap. Although magnolias under environmental conditions common in Florida forests do not seem to establish young trees of their kind in the shade of the parent forest, the species is nevertheless the climax tree because magnolia can by starting in the shade of other forest trees replace them, while on the contrary no other tree is able to start and persist under it. It needs to be pointed out that the development, consummation, and perpetuation of a magnolia climax, or for that matter a magnolia-beech climax, as influenced by light conditions, soil constantly disturbed by hogs, depletion of seed under parent trees by the same swine and native animals, and meager leaf mold produced by the leathery foliage.of magnolias present puzzling problems awaiting solution. However, further discussion of a magnolia climax with various attending aspects regarding its establishment and continuation hardly lies within the province of this work.
In connection with the Daytona Beach dunes it was pointed out that during the very progress of the writer's field observation residential development was erasing scenic seaside dunes. Only recently operations have begun at Lanark which are obliterating several miles of ancient dunes and one of the few Magnolia climaxes on the northwest coast. If the dunes were left intact, a climax forest would eventually reappear on them; but the dunes themselves, once destroyed as physiographic features, will not return. Practically speaking these ancient dunes are gone forever. To compensate for these drastic yet necessary losses, we should strive all the harder to set aside, for all time, at least some of the remaining remnants that have nothing to commend them except scientific value, scenic interest, and primitive beauty.
BEACON HILL
The area represented in the Beacon Hill profile is situated about twelve miles west of Port St. Joe, Bay County. A section of dunes about a half a mile wide along the coast and running about a mile inlandward from beach to hammock is represented in this study. Small active dunes near the beach are of relatively recent times, while those farther inland of the same series are older quiescent dunes that must go to the geologic past. For the present, at least, no decided evidence of retreating or advancing shoreline exists; locally, however, small dunes are




in different stages of progress just behind the upper beach. Farther back, as in other localities of northwest gulf coast, mainland, and barrier-islands like Dog Island, Santa Rosa Island and Indian Pass that same main dune ridge so characteristic of the east coast is present. While it reaches elevations of twenty-five to thirty-five feet in places, it is here only about fifteen feet high, yet that height together with its width make it distinctive.68 Its prominence may be due to circumstances similar to those suggested for bringing about the principal ridge of the east coast.69 Flatwoods Swale
An important topographic feature here influencing the vegetation profoundly is the elongated trough just behind and parallel to the conspicuous ridge. This trough in places fifty to one hundred feet or more wide is very flat and stabilized with very representative flatwoods vegetation. Whatever the explanation of this long flat swale appearing as an interlude between the main foredune ridge and the continued series farther back, it seems with its flatwoods species and soil totally distinct and apart from the dune bordering it on both sides. The habitat with its black water-logged soils is completely dominated by a close cover of many species of herbs and shrubs. Dune plants so common on the dunes nearby are conspicuous by their absence in this wet area; yet twin live-oaks, yaupon, rose-
68 Martens, James H. C, Beaches of Florida, p. 112; Cooke, C. Wythe, Scenery of Florida, p. 76; and Vernon, Robert O., Geology of Holmes and Washington Counties, Florida: E'lorida Dept. of Conservation, Geol. Dept. Bull. 21, p. 19, 1942.
69 Johnson, D. W., Shore processes and shoreline development, pp. 440-442. See quotation from Johnson page 45.
EXPLANATION OF PLATE 14.
Northwest gulf coast dunes. Top: blow-out invading freshwater pond and smothering saw-palmettoes. If the advance is not too rapid, a number of woody plants can survive by sending out adventitious roots, Long Beach, Bay County. Middle: low expansive dunes made by a sweet-rush or sand coco-grass, Gyperus LeContei. Because of the high water requirement these dunes form only in low areas and seldom go above a few feet in height. Their elongated and profusely rooted sub-surface stems and many roots, aerial stems and leaves bind the damp sand with an even surface. Dark green porcupine dunes by Hypericum aspalathoides in rear. Panama City Beach. Bottom: Flatwoods trough with many typical species not ordinarily found in dunes. To left of the highway is a continuation of old low dunes alternated by low swales with flatwoods plants. Foreground shows dune encroaching on flatwoods. In the flatwoods shown are small dune islands with characteristic dune species. Dark cedar-like shrub is rosemary. Pines in background are mostly slash-pines. Bay County five miles west of Beacon Hill.


Sesuvium_Portulacastrum
Atrip lex nrenaria Cnnrinln Party I on Polygonum glaucum Hydrocotyle hnnariensi*; Raimnnnia humifusa
Hydrocotyle honariensis Raimannia humifusa
Uniola paniculata_
RivanPa niimntnan
Qhrysoma pauciflosculosa Chrysoma paucifiosculosa
Ou firms geminata Ilex vomitoria Serenoa repens Ceratiola ericoides
Quercus myrtifotia
_Pinus palustris
Quercus geminata Ilex vam itoria Serenaa repens
Ceratiola ericoides Quercus myrtifn Ha Qdontanychia erecta
_ Pinus palustris
Flatwoods species Flatwoods .species


Ohrysopsjs floridaon_
Chrysoma pauciflosculnsa_
_Pin us pnluatrfs_
_ilex_vnmitnrin_
-Polygonum_g/aucum._
_Cnnrnriinn rnnesrerx;_
_Odontonychia erecfa_
_C.eratinla erinnides_
__Que mis geminntn_
_._Quercus myrti folia_
_Serennn repens_
_Pin us r.lausa_
_Geobalanus nhlongifnlius_
_Gtinopodium_coccineum_
_Gtierr.tK r.hnnmnnii___-
_Mnnnnlin_grnndiflnrn-
___ufrnrin ginhrn nnri nth pr hnrriwnnris
Plate 15b.Beacon Hill profile continuation.


mary, scrub-oak, shrubby goldenrod, and saw-palmetto missing here do grow along a bordering fringe of sand only a few inches higher and spilling over from the invading foredune which is locally moving toward and superimposing itself on the flatwoods. In the midst of this flatwoods the writer observed a small island dune fifteen feet across and two feet high supporting dune species like twin live-oak, shrubby goldenrod, rosemary, Odontonychia erecta. The high water table of the soil together with factors like poor air relations although favorable to the flatwoods flora precludes the dune plants apparently adapted to less water, better aeration, and other conditions. The fact that only a foot or more elevation above the flatwoods brings the dune species demonstrates with what nicety they adhere to or avoid a given set of environmental conditions.
Establishment of Oaks_____________________________________________________
There is every indication that twin live-oak is the pioneer among the dune oaks. That is to say, it occurs first, but seems to start only in the lower moist sands, withstanding considerable undermining or covering later by means of copious underground stem and root development. Scrub-oak tends to appear later on the more stable dunes but then only in the milder and moister areas. It, too, is capable of underground development and spreading but seems here not as hardy or adaptable as twin live-oak. Chapman's-oak is the last of these three dune oaks to appear. It seems different in its demands than either of the other two being able to germinate (as previously observed) in the shade of twin live-oak, scrub-oak, or other woody plants. If one goes on back into this area for a distance of a mile or so from the seacoast, he will find spruce-pine groves well developed and plainly in possession. Where the spruce-pine takes over, the first to fade out is twin live-oak, next scrub-oak, and last Chapman's-oak. The palmetto also begins to thin out. Conradina canescens and shrubby goldenrod persist only as relics. But as indicators of the moisture and more stable conditions, red-bay, sarsaparilla-vine may be found growing in the shade of these spruce-pines.
Hardwood Climax
Farther back in areas where the dunes are still older or farther along in plant succession, spruce-pine is almost entirely replaced by magnolias, pignut, holly, laurel-oak, large Chap-


man's-oaks, the latter as relics, with well-developed undergrowth of wild-olive, French-mulberry, yaupon, small-fruited pawpaw, sparkleberry, sarsaparilla-vine, and some palmettoes. In other words, there are here the beginnings of a typical hammock, which, barring catastrophe, will develop into a climax dominated by magnolia. Only here and there are old relic spruce-pines harking back to the previous stage in this successional development. The spruce-pines relate the past; the young magnolias predict the future.
Plant List
Sea-oats zone
Sesuvhim Portulacastrum Atriplex arenaria Capriola Dactylon Polygonum glaucum Hydrocotyle bonariensis Raimannia humifusa Uniola paniculata Ipomoea Pes-Caprae Croton punctatus Chamaesyce Ingallsii Fimbristylis castanea Phyla nodiflora Spartina patens Paspalum vaginatum Odontonychia erecta Heterotheca subaxillaris
Scrubspruce-pine zone Chrysoma pauciflosculosa Quercus geminata Ilex vomitoria Ceratiola ericoides Pinus palustris Bivonea stimulosa Quercus myrtifolia Serenoa repens Odontonychia erecta Chrysopsis fioridana Polygonella polygama Conradina canescens Pinus clausa Tamala Borbonia Geobalanns oblongifolius Clinopodium coccineum Quercus Chapmanii Smilax pumila Xolisma ferruginea
Flatwoods
Eleocharis caribaea Drosera Tracyi Syngonanthus flavidulus
Sea-purslane t
Beach-orach
Bermuda grass
Knotweed t
Seaside-pennywort *
Seaside evening-primrose
Sea-oat
Railroad-vine
Silver-leaf croton
Creeping-spurge*
Sand-rush *
Cape-weed
Salt-grass
Salt joint-grass
Camphor-plant
Shrubby goldenrod *
Twin live-oak
Yaupon
Rosemary
Slash-pine
Spurge-nettle
Scrub-oak
Saw-palmetto
Golden-aster t October-flower Blue-sage % Spruce-pine Red-bay Gopher-apple t Basil f
Chapman's-oak Sarsaparilla-vine Stagger-bush t
Spike-rush t
Dew-thread
Shoe-button
t Generic common names.
i Departure from Small's manual as to common name. After Penfound and O'Neill.


PLANT LIST (continued) Ascyrum stans Lasiococcus Mosieri Sari'acenia flava Erigeron vermis Hydrocotyle bonariensis Desmothamnus lucidus Hypericum aspalathoides Ilex glabra
Lycopodium alopecuroides L. % Stomoisia cornuta Cyanococcus Myrsinites Cerothamnus ceriferus Aristida strict a Hardwood hammock Symplocos tinctoria Amarolea americana Hicoria glabra Asimina parviflora Smilax pumila Batodendron arboreum Callicarpa americana Cerothamnus ceriferus Serenoa repens Quercus Chapmanii Pinus clausa Quercus myrtifolia Quercus geminata Ilex opaca Ilex vomitoria Quercus laurifolia Parthenocissus quinquefolia Toxicodendron radicans
St. Peter's-wort
Dwarf-huckleberry f
Trumpet
Fleabane f
Seaside-pennywort *
Fetter-bush
St. John's-wort t
Gallberry
Club-moss
Bladder-wort family Blueberry t Wax-myrtle Wire-grass
Sweetleaf Wild-olive f Pignut
Small-fruited pawpaw
Sparkleberry
Sarsaparilla vine
French-mulberry
Wax-myrtle
Saw-palmetto
Chapman's-oak
Spruce-pine
Scrub-oak
Twin live-oak
Holly
Yaupon
Laurel-oak
Virginia-creeper
Poison-ivy
DUNE PATTERNS AS DETERMINED BY PLANTS
The efficiency of certain kinds of herbs as dune builders was considered in the earlier section on dune-building plants; and the relation of various woody species to dune dynamics received attention in connection with the Ponte Vedra profile. The following paragraphs will deal with correlation existing between plants and dune design. The reader should also review section on dune-building plants, Plates 1, 2, 5, 14, and Figures 5, 6, and 7.
f Generic common names.
J Departure from Small's manual as to common name. After Penfound and O'Neill.
EXPLANATION OF PLATE 16. Dune types and associated plants on northwest gulf coast. Top: stable 30-foot rear dune occupied by twin live-oak, scrub-oak Chapman's-oak, rosemary and spruce pine. Middle: low dune formed by sea-purslane in moist flat areas. Bottom: Ephemeral porcupine dunes started in low places by Hypericum aspalathoides. Note white sand held by dense branches of plant. These dunelets often disintegrate with death of the plant when the mounds rise approximately two or three feet or so above the moist substratum.


Plate 16.Dune types and associated plants.


* After Penfound and O'Neill.
Hydrocotyle bonariensis: seaside pennywort
The marsh-pennywort, a perennial herb with slender and shallow subterrannean stems, often thrives in low wet sands; but once established in depressions, the slender rhizomes take the plant up the slopes of the highest dune as they sneak around and in between areas left bare by sea-oats. Only dense growth of other plants is able to shade or crowd it out. And yet the species, because of its sparsely branching rhizomes and limited roots, can in itself not make a very high dune. The marsh-pennywort is able to make rapid horrizontal advances; yet it lacks a close network of underground parts with which to hold anything except damp sand; consequently, when sand accumulates upward to the level of drying, it blows away from the loosely branched stems. Pure pennywort dunes are, therefore, as a rule, flat and very little above the damp surroundings.
Phyla nodiflora: Cape-weed
This plant, very similar to the seaside-pennywort in shallow roots, slight branching, and habitat preference, is also associated with flat dunes of meager altitude, whose sands, poorly anchored, are when dry easily taken by winds.
Chamaesyce Ingallsii: creeping spurge *
Although this spurge is very common on fresh sand dunes, the plant is worthless as a builder. This small annual with leaves and stems flat against the surface grows only where there is slight movement of sand. It will grow in low areas occasionally washed by salt, but not where much sand is on the march; for it can make little adjustment to the heaping of sand.
Cyyerus LeContei: sand coco-grass*
A colony of sand coco-grass, because of great regularity and frequency of underground branching and emergence, presents small shoots spaced more or less in row pattern (Plate 16). With a closely connected rhizome and root system below the surface, the species tucks the sand effectively about it, so that its dunes are usually of smooth and convex contour. Requiring considerable water, however, the plant ordinarily limits the height of the mound to three feet, or thereabouts.


Uniola paniculata: sea-oats
Quite in contrast to Cyperus LeContei dunes, the sea-oak constructs shaggy mounds of the greatest elevation attained by herbs. Sea-oat tufts, dishevelled-looking in themselves, take the sand high enough to allow surface drying. Wind scouring between the plants produces an unevenness in sand surface which accentuates the raggedness. At Panama City Beach, there is an immense complex blow-out showing great variety of
Figure 19.Sea-oat and saw-palmetto dunes at Indian Pass, Gulf County. Sea-oat dune, foreground and rear. Saw palmetto dune left of center. Cabbage-palms and hardwoods on leeward side of old dune, rear. Note the sloping anchored margin of sea-oats and the undermined edge of saw-palmetto.
dunes J3and_movement. Here Cyperus dunes leave off at two or three foot levels and sea-oats, beginning at about that altitude, raise the embryonic dunes still higher. Because of an extremely tough and long enduring under surface tangle of rhizomes and roots which ramify in the sand in several stories, sea-oats make an excellent sand binder. This deep system of roots and stems keeps them in touch with reserve water in the depths below. Contrary to expectation, dune sands have much more water in the subsoil layer than the dry surface indicates. Moreover, the tough, rolled-in leaves of sea-oats enable the plant to economize on the water that the roots draw from the


soil to the top of a twenty-five or thirty-five foot dune. Often where disintegration is in progress by winds undermining the sides of a dwindling dune there remains perched on top a ragged matrix of roots, stems, and leaves fighting against an-
Figure 20.Low young sea-oats dune ridge west of Panama City Beach. From Cooke, Scenery of Florida, Fla. Geol. Surv. Bull. 17, 1939.
Figure 21.High old blow-out ridge with sea-oats yielding to undermining winds. Five miles east of Camp Walton, Santa Rosa Island. From Cooke, Scenery of Florida, Fla. Geol. Surv. Bull. 17, 1939.


nihilation. Tousle-topped remnants like these have been called haystack dunes.70
Croton punctatus: silver-leaf croton
At Indian Pass, Gulf County, is a wide beach plain with considerable embryonic dune activity and variety. At one stretch is a long row of croton sand mounds marking some former wave-washed debris, which favored lodgement and establishment of the plants. Not any of these dunes is more than a few yards across nor more than three or four feet high. The reason for the small dunes seems to lie in the fact that these shrubby perennials, because of meager and weak adventitious roots, are not able to lift themselves very high above the wet beach sands. These plants have also been seen in large colonies near the top of blow-outs at Ponte Vedra. But it appears that they were there on a stabilized top before the advent of the blow-out.
Iva imbricata: a marsh-elder
With a strong system of rhizomes and adventitious roots, this marsh-elder makes gently rounded dunes of low stature at the youngest fore-ridges of the beach. The author has never seen any pure stand of marsh-elder dunes more than three or four feet high, yet strangely enough he found these plants sharing the habitat with croton at the top of the Ponte Vedra blow-out. See Plate 2.
Salsola Kali: saltwort
One autumn at Cochran's Beach, the writer saw a striking row of saltwort plants at a common level of shore debris where these seeds had been lodged. Sand about their stems indicated incipient dunes; but the following winter plants and dunes had vanished with the short life of these annual plants.
Hypericum aspalathoides: St. Johns'-wort
Ordinarily this St. John's-wort grows in wet depressions. However, at Panama City Beach is a long flat trough behind and parallel to the main dune ridge. Here there are places which have been wet enough for the establishment of St. John's-wort. But because of sand that travels along this region of dune dynamics, the plants gathering the sand have been raised above
Penfound, Wm. T,, and O'Neill, M. E., The vegetation of Cat Island, Mississippi: Ecology, vol. 15, no. 1, p. 8, 1934.


EXPLANATION OF PLATE 17.
Northwest gulf coast dune scenes. Top: oak skeleton in plant ceme-tary of a blow-out, Panama City Beach. Middle: Deer-moss lichen and spruce-pine, Cochran's Beach, Franklin County. Bottom: remnant haystack dune with sea-oat and magnolia left in Panama City Beach blow-out.
the lowest wet levels. Low and thickly branched, this St. John's-wort makes excellent, though small, sand traps. So here is found a group of porcupine-like sand mounds, not exceeding three feet, bristling with protruding tips of dark shoots (PL 16). The prevailing winds have stream-lined them with a typical asymmetry. At the three-foot altitude are many dead branches and sometimes completely dead plants. A little digging shows a rather weak root system of limited depth. These plants depend on a more or less permanent water table not far below the flat surface. When the sands and branching shoots working together, raise the sand dunelet in the proximity of three feet, the whole structure collapses because the roots are now far above the permanent water to absorb enough to keep these semi-aquatic plants alive. The plant dies and the dune crumbles.
Ilex vomitoria: yaupon
On Dog Island, Franklin County, are remnant dunes of isolated clumps of yaupons. At one time these yaupon dunes stood in the way of aeolian sand which settled over and about the shrubs. The stems responding with profuse branching and copious adventitious roots formed thus a mass of interlacing woody growth filled with sand. With the removal of sand from all around the clumps, these masses stand now as relic monad-nocks of shrubbery and sand. The foliage is so dense and green on these neatly trimmed biscuit dunes that the sand held high and tightly within the plant hardly shows through the leaves. Very similar dunes are often related to twin live-oaks. See Plate 1.
Serenoa repens: saw-palmetto
Previously it has been indicated that saw-palmettoes always present in a dune system are, because of their sluggish growth, poor dune builders. In the flats of the Panama City Beach complex young palmettoes are starting from a moist sand and are stopping sand brought in by the wind. If the vertical accumulation is not too rapid, the plants may be able to keep just ahead, but that is all. Palmettoes do not spread laterally


Plate 17.Northwest gulf coast dune scenes.


in such gathering sands; they only grow up, attempting to keep their buds and fan-shaped leaves free. Since there is no lateral development, the plants gain no ground. Their only chance of survival lies in sea-oats coming to the rescue. Palmettoes gain territory only in a stabilized sandold dunes, flatwoods, or scrub. When sea-oats are undermined, the reaching rhizomes will re-establish themselves when the merest sand hill reappears in proximity. Not so with palmetto. In accumulating sand, the rhizomes grow upward, not laterally. Sometimes many of them which should grow horizontally form a common center; bunched in this manner, all of them seem chased skyward by the accumulating sand. When now a blow-out overtakes such a clump, the remnants make a turret dune or appear like a stockade of crowded vertical stems where eddying winds scour a deep encircling trough. See frontispiece and Plate 1.
DUNE MIGRATION
In the dune complex of Panama City Beach, the writer studied a dead slash-pine with erect trunk, six feet high. At the top there remained a dead end only three inches in diameter. Just below this small end the trunk became abruptly twelve inches across. And from this large diameter at a five-foot height, there issued one forty-foot horizontal branch also about twelve inches in diameter at the erect trunk from which it came. The extreme end of this crooked branch still leaned on a dune which was moving away from the pine.
It was soon apparent that many years ago a moving dune overtook this pine when it was twelve or fourteen feet high the size of the small end of the erect trunk by comparison with normal living slash-pine would indicate that height. As the sand drifted up, the top was killed; but a lateral branch growing away from the moving sand managed to escape complete burial. The sand came on; after many years the lateral branch, too, succumbed and, of course, with it, the whole tree. Eventually, by continued migration of the dune the buried trunk and limb were uncovered by the same kind of wind that once smothered them. And here now stands the dead tree giving its own history.
The writer secured an inkling of its past by a growth ring study of this dead tree in comparison with living slash-pines. Cores taken from the trunk with a special plugging device re-