• TABLE OF CONTENTS
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 Title Page
 Acknowledgement
 Table of Contents
 Abstract
 Introduction
 Taxonomic review
 Morphological description
 Comparative morphology of the leaf...
 Comparative anatomy of the stem...
 Pollen morphology
 Conclusion
 Appendix: Synopsis of infrageneric...
 Bibliography
 Biographical sketch














Title: Systematic studies of cultivated species of Codonanthe (Martius) Hanstein and Nematanthus Schrader (Gesneriaceae)
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 Material Information
Title: Systematic studies of cultivated species of Codonanthe (Martius) Hanstein and Nematanthus Schrader (Gesneriaceae)
Physical Description: vi, 167 leaves : ill. ; 28 cm.
Language: English
Creator: Yuen, Clayton Kazuo Kwock Hung, 1953-
Copyright Date: 1982
 Subjects
Subject: Codonanthe   ( lcsh )
Nematanthus   ( lcsh )
Gesneriaceae   ( lcsh )
Horticultural Science thesis Ph. D
Dissertations, Academic -- Horticultural Science -- UF
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by Clayton Kazuo Kwock Hung Yuen.
Thesis: Thesis (Ph. D.)--University of Florida, 1982.
Bibliography: Bibliography: leaves 161-166.
General Note: Typescript.
General Note: Vita.
 Record Information
Bibliographic ID: UF00099232
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: alephbibnum - 000319146
oclc - 09318434
notis - ABU5997

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Table of Contents
    Title Page
        Page i
    Acknowledgement
        Page ii
    Table of Contents
        Page iii
        Page iv
    Abstract
        Page v
        Page vi
    Introduction
        Page 1
        Page 2
    Taxonomic review
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
    Morphological description
        Page 8
        Page 9
        Page 10
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    Comparative morphology of the leaf epidermis
        Page 68
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    Comparative anatomy of the stem and leaf
        Page 93
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    Pollen morphology
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    Conclusion
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    Appendix: Synopsis of infrageneric taxa of codonanthe and nematanthus
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    Bibliography
        Page 161
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    Biographical sketch
        Page 167
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Full Text










SYSTEMATIC STUDIES OF CULTIVATED SPECIES OF
Codonanthe (MARTIUS) HANSTEIN AND Nematanthus SCHRADER (GESNERIACEAE)








BY






CLAYTON KAZUO KWOCK HUNG YUEN


A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL
OF THE UNIVERSITY OF FLORIDA IN
PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR THE DEGREE OF DOCTOR OF PHILOSOPHY

UNIVERSITY OF FLORIDA















ACKNOWLEDGEMENTS


I wish to sincerely thank Dr. Thomas J. Sheehan, Professor,

Department of Ornamental Horticulture, for his advice and assistance

during the course of this research and manuscript preparation.

Very special thanks are offered to Dr. Bijan Dehgan, Assistant

Professor, Department of Ornamental Horticulture, for his technical

expertise, suggestions and support during all phases of the research

project, for his invaluable criticism of the manuscript, and for his

friendship.

I am indebted to Dr. Hans Wiehler, Director of the Gesneriad

Research Foundation, Sarasota, Florida, for serving as an adjunct

professor to the committee, for supplying the plant material, and for

providing guidance during the research project and preparation of the

manuscript.

Thanks are also extended to the other members of the committee, Dr.

William Louis Stern, Professor, Department of Botany and Dr. Paul M.

Lyrene, Associate Professor, Department of Fruit Crops, for their

suggestions and criticisms of this research and manuscript preparation.

I would like to acknowledge Dr. Laurence E. Skog, Department of

Botany, Smithsonian Institution, for his assistance in my herbarium

work, Dr. Margaret H. Stone, Department of Botany, University of

Florida, for her enthusiasm and support, and Mr. William R. Saylor for

supplying additional plant material.















TABLE OF CONTENTS


PAGE

ACKNOWLEDGEMENTS.................... ............................. ii

ABSTRACT ...................................................... v

INTRODUCTION ................................................................ 1

CHAPTER

I. TAXONOMIC REVIEW.......................................... 3

II. MORPHOLOGICAL DESCRIPTION................................. 8

Growth Habit ...................... ........ ....... ......... 8
Root.................................................... 9
Stem.................................................... 10
Leaf..................................................... 11
Inflorescence............................................ 14
Flower...................................... .......... 14
Fruit.................................................... 18
Seed and Seedling......... ............................ .... 19
Pollination ................... ................, ........ 20
Chromosome Number ................................... 24
Distribution.......... ................................ 25

III. COMPARATIVE MORPHOLOGY OF THE LEAF EPIDERMIS............. 68

Introduction............................................ 68
Materials and Methods.................................... 68
Observations.................... ...... ............. 69
Discussion ............................................. 77

IV. COMPARATIVE ANATOMY OF THE STEM AND LEAF.................... 93

Introduction ............... .......................... 93
Materials and Methods.................................... 93
Observations.......................................... 94
Discussion................................................ 99










V. POLLEN MORPHOLOGY ......................................... 109

Introduction............................................ 109
Materials and Methods................................... 110
Observations............................................ 110
Discussion.......................................... .... 115

VI. CONCLUSION............... ................ ... ........... 142

APPENDIX: SYNOPSIS OF INFRAGENERIC TAXA............................ 150

Description of the Genera, Subgenera and Sections......... 150
Diagnostic Key to the Genera, Subgenera and Sections..... 156
Checklist of Known Species............................... 157

LITERATURE CITED.................................................. 161

BIOGRAPHICAL SKETCH............................................... 167














Abstract of Dissertation Presented to the Graduate Council
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy

SYSTEMATIC STUDIES OF CULTIVATED SPECIES OF
Codonanthe (MARTIUS) HANSTEIN AND Nematanthus SCHRADER (GESNERIACEAE)

By

Clayton Kazuo Kwock Hung Yuen

December 1982

Chairman: Thomas J. Sheehan
Major Department: Horticultural Science

Codonanthe (Martius) Hanstein and Nematanthus Schrader

(Gesneriaceae) are morphologically distinct genera of the evergreen and

deciduous rain forests of Central and South America. Two subgenera and

two sections had been recognized to accommodate the fourteen cultivated

species of Codonanthe, whereas no subgeneric ranks were previously

reported for the ten cultivated species of Nematanthus. Hybridizations

between Codonanthe and Nematanthus have produced progeny that display a

high degree of fertility, indicating that the species of Codonanthe and

Nematanthus are closely related. The present study examined the

species of Codonanthe and Nematanthus and attempted to resolve the

relationship of species between genera and within each genus.

Conventional taxonomic methods and systematic techniques of light and

electron microscopy, microtomy, leaf clearings and karyology were

utilized in the study of live plant material.

Flowers of Codonanthe species have obliquely funnelform-ventricose

corollas that are primarily white and are presumably pollinated by








Euglossine bees, whereas species of Nematanthus have pouched corollas

that are basically orange, red, pink or yellow and are presumably

pollinated by hummingbirds. Possession of such differing corolla types

and pollinators reproductively isolate these two genera, possibly

indicating that Codonanthe and Nematanthus should remain as distinct

taxa.

Species of subgenus Codonanthe section Codonanthe have orange

berries, a diploid chromosome number of n=8, and a unilacunar nodal

anatomy (except C. carnosa and C. gracilis), lack extrafloral

nectaries, and are indigenous to southeastern Brazil. Species of

subgenus Codonanthe section Spathuliformae and subgenus Codonanthella

have red, pink or purple berries or yellow-green fleshy capsules, a

tetraploid chromosome number of n=16, and a trilacunar, split-lateral

nodal anatomy, possess extrafloral nestaries, and are geographically

widespread from southern Mexico through Central America to northern

South America. Nematanthus crassifolius, N. fissus, N. fritschii, N.

hirtellus, N. maculatus and N. perianthomegus have a shrubby growth

habit, trilacunar, spilt-lateral nodal anatomy, and resupinate flowers,

whereas N. gregarius, N. nervous, N. strigillosus and N. wettsteinii

have a viny growth habit, unilacunar nodal anatomy, and nonresupinate

flowers.

On the basis of these observations, sections Nematanthus and

Parvifolius are established to accommodate the species of Nematanthus,

and it is acknowledged that further studies are required before any

conclusions are made on the relationships of the infrageneric taxa of

Codonanthe. A synopsis of the infrageneric taxa and revised

classification of the genera Codonanthe and Nematanthus is presented.














INTRODUCTION


Gesneriads have been in the horticultural trade for many years and

are becoming very popular with the current indoor plant revolution.

Potted plants of the Florist Gloxinia (Sinningia speciosa), African

Violet (Saintpaulia spp.) and Cape Primrose (Streptocarpus spp.) are

grown in the home, often in light gardens, and in the greenhouse.

Nurserymen have recognized that epiphytic and terrestrial gesneriads

are ideal candidates for hanging baskets. Species of Aeschynanthus

(Lipstick Plant), Codonanthe, Columnea, Episcia (Flame Violet) and

Nematanthus (Goldfish Plant) are widely cultivated in hanging baskets

for their colorful flowers and foliage (Elbert & Elbert, 1976).

Plantsmen have hybridized many species of Gesneriaceae in an

attempt to produce new cultivars. Interspecific crosses have generally

yielded fertile progeny, whereas intergeneric combinations have always

resulted in offspring of very low fertility to sterility (Wiehler,

1979b). An intergeneric hybrid between Codonanthe and Nematanthus was

created in 1977 and designated X Codonatanthus (Saylor, 1978a). This

was the first intergeneric combination that displayed a high degree of

fertility, indicating that species of Codonanthe and Nematanthus may be

more closely related than realized.

A doctoral program was initiated in 1979 to 1) examine species of

Codonanthe and Nematanthus in cultivation, 2) determine the relationship

of species between genera and within each genus, and 3) provide a





2


synopsis of the infrageneric taxa of Codonanthe and Nematanthus.

Conventional taxonomic observations were made of the cultivated species

of the two genera to serve as the basis of this thesis.

Systematic methods were employed in an attempt to discover

additional characters of taxonomic utility. Light and electron

microscopy, microtomy, leaf clearing, chromosome techniques and

hybridizations were applied to the study of live plant material. These

tools of taxonomy were used to examine the morphology of the leaf

epidermis and pollen, and anatomy of the stem and leaf. It is the

additive nature of taxonomy that incorporates information from many

differing sources to strengthen any final decision of a possible new

classification.















CHAPTER I
TAXONOMIC REVIEW


Gesneriaceae Dumortier consists of three

subfamilies--Gesnerioideae, Coronantheroideae Wiehler and

Cyrtandroideae Endlicher (Wiehler, 1979b). Gesnerioideae includes 5

tribes, 54 genera and over 1300 species distributed throughout the

Neotropics. Coronantheroideae includes 1 tribe, 9 genera and about 20

species in southern Chile, the South Pacific islands and Australia.

Cyrtandroideae is composed of 4 tribes, 63 genera and over 1550 species

mainly in the Paleotropics. Besides differing distributions, the

subfamilies are distinguished by seedling morphology (e.g.,

anisocotyledonous seedlings in Cyrtandroideae and isocotyledonous

seedlings in Gesnerioideae and Coronantheroideae).

Five tribes that form Gesnerioideae are Gesnerieae, Napeantheae

Wiehler, Beslerieae Bartling & Wendland, Gloxinieae Fritsch and

Episcieae Endlicher. Gesnerieae and Napeantheae are monogeneric, while

Beslerieae is composed of seven genera. Cloxinieae and Episcieae are

the larger tribes of this subfamily, and comprised 24 and 21 genera,

respectively. Chromosome number serves as a distinguishing character

in these tribes--i.e., Episcieae, n = 8, 9; Gloxinieae, n = 10, 11, 12,

13; Gesnerieae, n = 14; Beslerieae, n = 16; Napeantheae, unknown

(Wiehler, 1979b).

Episcieae is the largest tribe of Gesnerioideae, with over 630

species in 21 genera. Wiehler (1979b) discusses three features of

3








evolutionary significance intrinsic to Episcieae: a) an unusual

trilacunar nodal anatomy with split lateral bundles, b) a predominance

of epiphytic species, and c) ornithophily and euglossophily as the

primary mode of pollination. Also, there are usually two enlarged,

connate glands at the base of the ovary serving as a nectary in the

hummingbird-pollinated and euglossine bee-pollinated flowers. The fruit

is a berry or a fleshy capsule. Although the majority of genera in

Episcieae have a chromosome number of n = 9, Codonanthe and Nematanthus

are unique in possessing a chromosome number of n = 8.

A chronologically arranged taxonomic history of Codonanthe and

Nematanthus is presented in Table I-1. A current classification system

of these two genera according to Wiehler (1979b, 1982, & personal

communication) is shown in Table 1-2, with the known cultivated species

tabulated.








Table I-1. Taxonomic history of the genera Codonanthe and Nematanthus.


DATE TAXA


EVENT


1821 Nematanthus Schrader



1829 Hypocyrta Martius &
Hypocyrta section
Codonanthe Martius

1854 Codonanthe (Martius)
Hanstein


1855 Coccanthera C. Koch
& Hanstein




1934 Codonanthoosis
Mansfeld


1971 X Hypotanthus Saylor




1973 Codonanthe section
Codonanthopsis
(Mansfeld) H. E.
Moore

1973 Nematanthus
Schrader


1978 X Codonatanthus
Saylor


The genus Nematanthus is first established
in Gottingische gelehrte Anzeigen 1821
(2): 718.

The genus Hypocyrta is first established
with the section Codonanthe, in Nova
Genera et Species Plantarum 3: 49.

Hypocyrta section Codonanthe is elevated
to the genus level with Codonanthe as the
conserved name, in Linnaea 26: 209.

A new genus established with its
lectotype relegated to the synonymy of
Codonanthe, in Index Seminum in Horto
Regio Botanico Berolinensi 1855:
Appendix 17.

The genus Codonanthopsis is first
established, in Repertorium Specierum
Novarum Regni Vegetabilis 36: 120.

New intergeneric taxon was created due
to the cross of Hypocyrta and
Nematanthus, in Gloxinian 21:
20-21, 31.

The genus Codonanthoosis is lowered
to the sectional level of the genus
Codonanthe, in Baileya 19: 4-23.


Moore combines many species of the genera
Nematanthus and Hypocyrta into one
genus, in Baileya 19: 35-41.

New intergeneric taxon was created due
to the cross of Codonanthe and
Nematanthus, in CrossWords 2: 11-12,
Selbyana 5: 1-3.










Table I-1 continued.

DATE TAXA

1979 Codonanthe (Martius)
Hanstein &
Codonanthopsis
Mansfeld

1979 Codonanthe subgenus
Codonanthella
Wiehler


1982 Codonanthe subgenus
Codonanthe section
Spathul iformae
L. B. Smith


EVENT


Wiehler regards Codonanthopsis as a
valid genus, in Wiehler, Ph. D.
dissertation.


New subgenus of Codonanthe established
based upon species having fleshy
capsules, in Wiehler, Ph. D.
dissertation.

New section of Codonanthe recognized
based upon species having purple, red
or pink berries, in Selbyana 6(in press)
and personal communication with
Wiehler.








Table 1-2. Current classification system of the cultivated species
in the Nematanthus according to Wiehler (1979b, 1982 and
personal communication).


GENUS Codonanthe (Martius) Hanstein

SUBGENUS Codonanthe

SECTION Codonanthe

1. C. carnosa (Gardner) Hanstein
2. C. devosiana Lemaire
3. C. digna Wiehler
4. C. gracilis (Martius) Hanstein
5. C. paula Wiehler

SECTION Spathuliformae L. B. Smith

6. C. calcarata (F.A.W. Miquel) Hanstein
7. C. corniculata Wiehler
8. C. crassifolia (Focke) Morton
9. C. uleana Fritsch


SUBGENUS Codonanthella Wiehler

10. C. caribaea Urban
11. C. chiricana Wiehler
12. C. elegans Wiehler
13. C. luteola Wiehler
14. C. macradenia Donnell-Smith


GENUS Nematanthus Schrader

1. N. crassifolius (Schott) Wiehler
2. N. fissus (Vellozo) L. Skog
3. N. fritschii Hoehne
4. N. gregarius D. Denham
5. N. hirtellus (Schott) Wiehler
6. N. maculatus (Fritsch) Wiehler
7. N. nervous (Fritsch) H. E. Moore
8. N. perianthomegus (Vellozo) H. E. Moore
9. N. strigillosus (Martius) H. E. Moore
10. N. wettsteinii (Fritsch) H. E. Moore


Accession Number


w-2199
W-2215
W-1139
W-2203
W-2386



W-2116
G-932
W-2531
W-1182



G-976
W-2267
W-2588
w-1630
W-2552


G-134
G-661
G-611
G-597
G-1092
W-2494
G-734
W-1718,W-2227
W-388
G-655















CHAPTER II
MORPHOLOGICAL DESCRIPTION


Descriptions of the cultivated species of Codonanthe and

Nematanthus species are based on the literature and personal

observations of live plant material cultivated in a growth room at the

Department of Ornamental Horticulture, University of Florida. The

growth room provided uniform conditions of 22-250C day temperature,

17-20 C night temperature, 4000-6000 Lux fluorescent lighting and a

fourteen hour daylength. Descriptive terminology is based on Radford

et al. (1974). Morphological characters of Codonanthe and Nematanthus

are tabulated in Table II-1 for ease of comparison, with the species

grouped into infrageneric categories based upon Wiehler (1979b, 1982 &

personal communication).



Growth Habit

Species of Codonanthe and Nematanthus are phanerophytes (Raunkiaer,

1934). They are perennials that are one-to-many feet tall, have their

vegetative buds fully exposed to surrounding air, and are epiphytes. As

epiphytes, these species are attached to and depend upon another plant

for physical support. Codonanthe and Nematanthus are among thirteen

epiphytic genera in the tribe Episcieae (comprise only 21 genera) and

28 epiphytic genera of Gesneriaceae (Wiehler, 1979b).








Codonanthe (Figures II-1 to II-3) and Nematanthus (Figures 11-4 to

II-5) species have a vine-like and/or shrub-like growth habit.

Vine-like species (e.g., C. carnosa, C. gracilis, N. strigillosus, N.

wettsteinii) possess stems that initially grow in an upright direction

with little branching. With continued growth and elongation, the stem

acquires a reclining, clambering or decumbent habit due to the

inability of the stem to support itself. Other species have a

pendulous mode of growth (e.g., C. elegans, C. luteola, C. macradenia)

or grow in an erect, shrub-like fashion (e.g., C. uleana, N.

crassifolius, N. maculatus, N. perianthomegus). Table II-I presents a

list of the cultivated species of Codonanthe and Nematanthus and their

growth habit types.





Root

Species of Codonanthe and Nematanthus have fine, thread-like

fibrous roots that arise adventitiously from the stem. Some species

possess pre-formed roots (e.g., C. elegans) or root initials (e.g., N.

hirtellus) at the nodes. Adventitious root development corresponds well

with the epiphytic habit of the plants. Epiphytes are better sustained

on a host if they are anchored to the substrate at numerous locations,

that is, attached by many roots. Also, a repent, spreading habit

promotes the proliferation of the original plant in such a way that if

a stem is severed, one or more individuals are formed. New plants have

excellent chances of survival since they already possess well-developed

roots.








In the ant-gardens of Codonanthe crassifolia, a mutualistic

association is maintained with an arboreal, carton-building ant.

Kleinfeldt (1978) proposes that the epiphyte's roots add structural

support to the ant nests. Seeds of C. crassifolia are often carried by

ants and placed in their nests (mode of seed dispersal). The seeds

soon germinate in the nutrient-rich detritus and permeate their roots

throughout the carton walls lending support to the framework of the

ant-gardens.





Stem

Codonanthe and Nematanthus species have herbaceous stems that are

suffrutescent. The stem epidermis is initially green with a smooth

texture in many species, with exceptions occurring in N. fissus

tomentosee indumentum) and N. strigillosus (strigose vestiture). The

transition from the herbaceous condition results in a woody stem with

greyish-tan to brown coloration. The texture may be smooth (e.g., C.

gracilis) to rough with a fissured appearance (e.g., N. perianthomegus).

Extrafloral nectaries are present at the nodes of some Codonanthe

species (e.g., C. crassifolia). These species are usually associated

with ant-gardens and possess nectaries which attract ants--the agents

of seed dispersal (Moore, 1973a; Kleinfeldt, 1978).

Table II-1 categorizes species of Codonanthe and Nematanthus into

two groups based upon stem size: a) 2-4 mm or b) 5-9 mm stem diameter.

This measurement is basically correlated to the growth habit of the

taxon. Vine-like plants have stems 2-4 mm in diameter, whereas a 5-9 mm

stem denotes a shrubby form. Most Codonanthe species have the small








stem size. Nematanthus gregarius, N. nervous, N. strigillosus and N.

wettsteinii form a distinct group of species with 2-4 mm stems and a

viny habit, while the other six Nematanthus species exhibit a shrubby

form with 5-9 mm stems.

Anatomical aspects of the stem are addressed in CHAPTER IV:

COMPARATIVE ANATOMY OF THE STEM AND LEAF.



Leaf

Leaf characters are summarized in Table II-1 and descriptions

follow Hickey's (1973) treatment with respect to architecture.

Anatomical features of the leaf are given in CHAPTER IV: COMPARATIVE

ANATOMY OF THE STEM AND LEAF.





Arrangement

Most species of Codonanthe and Nematanthus have isophyllous leaves

in an opposite arrangement. Leaves are basically decussate but a few

of the vine-like species have leaf blades oriented in a distichous-like

manner, that is, appearing 2-ranked with the leaves facing one

direction. For example, N. fissus, N. maculatus and N. perianthomegus

have leaf blades in a 4-ranked arrangement, whereas C. carnosa, C.

digna and C. gracilis have leaf blades in a 2-ranked placement.



Petiole

Most species of Codonanthe have rounded, green petioles (except C.

corniculata with reddish petioles). Nematanthus species are more

variable in possessing petioles that are slightly furrowed on the








adaxial surface (e.g., N. crassifolius) and/or with a red coloration

(e.g., N. fissus and N. hirtellus).

Petiole size may be classified into two length categories: a) 4-10

mm and b) 10-50 mm. Codonanthe species all possess 4-10 mm long

petioles (Figures II-6 to 11-8). Nematanthus gregarius, N. nervous, N.

strigillosus and N. wettsteinii also have 4-10 mm petioles (Figure

II-10), but the other six Nematanthus species exhibit petioles 10-50 mm

long (Figure 11-9).



Blade

Symmetry and Form. Codonanthe and Nematanthus are represented by

species that have leaf blades with a symmetrical or asymmetrical lamina

and/or base (Figures II-6 to II-10). Variations in leaf base balance

include a) symmetrical lamina and base (e.g., C. caribaea), b)

symmetrical lamina but an asymmetrical base (e.g., N. maculatus), c)

asymmetrical lamina but a symmetrical base (e.g., N. crassifolius), and

d) asymmetrical lamina and base (e.g., C. uleana).

Leaves in Codonanthe and Nematanthus are ovate (e.g., N.

nervouss, elliptic (e.g., N. fritschii) and obovate (e.g., N.

maculatus). Each leaf form is variously modified as narrow, normal or

wide (Hickey, 1973). For example, C. crassifolia, C. caribaea and C.

macradenia have elliptical leaves with a narrow, normal and wide form,

respectively. Also, Codonanthe and Nematanthus have leaf length

categories defined as a) 2-4 cm and b) 4-12 cm. Species of Codonanthe

subgenus Codonanthe section Codonanthe have ovate to elliptic leaves and

leaves 2-4 cm long (except C. gracilis), whereas species of subgenus

Codonanthe section Spathuliformae and subgenus Codonanthella have leaves








with an elliptic to obovate form and 4-12 cm long (except C. chiricana).

Nematanthus gregarius, N. nervous, N. strigillosus and N. wettsteinii

have leaves 2-4 cm long, whereas the other six Nematanthus species have

4-12 cm long leaves.

Apex and Base. Codonanthe and Nematanthus species have several

leaf apex and base shapes. Leaf apex shapes include acute (e.g., N.

strigillosus), acuminate (e.g., C. uleana), attenuate (e.g., N.

nervous) and obtuse (e.g., C. digna). Leaf base shapes include acute

(e.g., N. gregarius), obtuse (e.g., N. hirtellus), rounded (e.g., C.

paula) and cordate (e.g., C. gracilis).

Margin. Three types of leaf margins are evident in Codonanthe and

Nematanthus. Most species have entire margins such as C. caribaea and

N. wettsteinii. There are also species with slightly create margins

(e.g., C. chiricana and N. perianthomegus) and fully create margins

(e.g., C. calcarata and N. fissus).

Texture. Codonanthe and Nematanthus species exhibit generally

three forms of leaf texture--smooth (e.g., N. gregarius), puberulous

(e.g., N. hirtellus) and pubescent (e.g., N. fissus). Species of

subgenus Codonanthe section Spathuliformae and subgenus Codonanthella

display smooth leaf surfaces and species of subgenus Codonanthe section

Codonanthe (except C. gracilis) possess puberulous to pubescent leaves.

Leaf epidermis characters are discussed in CHAPTER III: COMPARATIVE

MORPHOLOGY OF THE LEAF EPIDERMIS, and include such morphological

aspects of leaf surface features as glandular and nonglandular

trichomes, stomata, extrafloral nectaries and surface ornamentation.

Coloration. Species of Codonanthe and Nematanthus have leaves that

are generally green adaxially with a lighter green on the abaxial








surface (e.g., C. devosiana and N. gregarius). Various other markings

or colorations are present and represented by C. gracilis (red

pigmentation at the leaf margins), C. elegans and N. fritschii (red

coloration at or around the midvein and/or secondary veins), N.

wettsteinii (red lamina only, with no colored veins), and C. carnosa

and C. paula (red coloration on total abaxial leaf surface).



Stipules

The leaves of Codonanthe and Nematanthus species are estipulate.





Inflorescence

The pair-flowered cyme is the basic inflorescence unit in

Gesnerioideae and is typical for the Gesneriaceae (Wiehler, 1979b).

Codonanthe and Nematanthus species possess a reduced cyme of one to

several flowers (appearing one at a time) in the upper leaf axils. The

inflorescence consists of short pedicels (except very long in N.

crassifolius and N. fritschii). Bracts are lacking (Moore, 1973a;

Wiehler, 1977, 1979a; Skog, 1978).



Flower

Orientation and Pedicel

The orientation of the flower is an important taxonomic trait in

delimiting Nematanthus species (Moore, 1973b). Flowers of N. gregarius,

N. nervous, N. strigillosus (Figures II-11E & II-11F) and N.

wettsteinii are consistently nonresupinate so that the pouch of the

corolla is in a normal, ventral abaxiall) position. The other six








species of Nematanthus (Figures II-11A to II-11D) display their flowers

with the corolla pouch in a dorsal adaxiall), resupinate position.

This resupinate flower orientation is the result of a 1800 twisting of

the pedicel from the ventral position.

Of the six Nematanthus species with resupinate flowers, N.

crassifolius and N. fritschii have pedicels that are 25-200 mm long and

flowers that are pendulous. Nematanthus fissus, N. hirtellus, N.

maculatus, N. perianthomegus, N. gregarius, N. nervous, N.

strigillosus and N. wettsteinii exhibit flowers that are erect in the

leaf axil with pedicels 3-25 mm long.

Species of Codonanthe (Figures II-12A & II-12B) have pedicels 3-25

mm long and nonresupinate flowers that are erect in the leaf axil.



Calyx

The calyx of Codonanthe and Nematanthus species is deeply 5-parted

with basally connate sepals and five unequal lobes. The dorsal lobe is

often recurved about the corolla spur with the ventral and lateral

lobes frequently connate towards the base presenting a bilabiate shape

(Figure II-12C). Codonanthe species have calyx lobes that are linear to

lanceolate, whereas species of Nematanthus possess linear to lanceolate

and ovate to elliptic calyx lobes. The lobes are variously entire to

shallow toothed, veined, glabrous to pubescent, and green to purple,

red and orange. Some species of Codonanthe (e.g., C. macradenia and C.

crassifolia) possess prominent red extrafloral nectaries (Figure

II-14C) in the sinuses of the calyx lobe margins (Moore, 1973a, 1973b).








Corolla

Codonanthe species (Figures II-12A & II-12B) possess an obliquely

funnelform-ventricose corolla with a base that is narrow and either

rounded (e.g., C. digna) or prominently spurred (e.g., C. chiricana).

The corolla tube gradually (e.g., C. crassifolia) or abruptly (e.g., C.

paula) broadens towards the throat or is somewhat dorsiventrally

compressed, arched and grooved (e.g., C. macradenia, Figures II-12E &

II-12F). The three lower lobes are spreading and larger than the upper

two lobes providing a bilabiate corolla configuration. The corolla is

situated obliquely within the calyx and in a horizontal position. It

is basically white or yellow (e.g., C. luteola), often with spots or

lines on the outer areas or on the lower surface of the throat that are

yellow, brown, pink, red, lilac or deep purple. The corolla is

glabrous to pubescent (Moore, 1973a).

Nematanthus species (Figures II-11A, II-11C & II-11E) have a

mildly to strongly ventricose corolla that is narrow above the base and

often with a short spur. The corolla tube gradually expands to a

broad, laterally compressed throat (e.g., N. fritschii), or quickly

widens to form a pouch that abruptly narrows to form a constricted

throat (e.g., N. nervouss, with five small rounded lobes. The latter

corolla configuration has been named by Wiehler (1979b) as a

Hypocyrta-type or hypocyrtoid corolla. The corolla tube is erect or

slightly oblique within the calyx. The corolla is scarlet, red, pink,

orange or yellow with maroon stripes, and glabrous to pubescent in

texture (Moore, 1971, 1973a).








Androecium

The four stamens in Codonanthe and Nematanthus species (Figures

II-12D & II-11B9 are didynamous, epipetalous and coherent, with the

anthers in a rectangular configuration. Species of Codonanthe are

unique in possessing anther locules separated spatially by a broad

connective and dehiscing by a pore near the apex of the thecae.

Species of Nematanthus have anthers that are more typical of genera of

the Gesnerioideae. They display narrow, elliptical anther connectives

and dehisce by a conventional longitudinal slit in the thecae (Wiehler,

1979b).



Gynoecium

Codonanthe and Nematanthus species (Figure II-14A) have a superior,

unilocular ovary that is composed of two united carpels (paracarpum,

cf., Ivanina, 1965). The parietal placenta is usually divided into two

and intrudes into the locule from the basal wall of the fruit. In

Codonanthe, the placenta forms two tuberculate projections. Ovules are

numerous and anatropous. The style (Figure II-14A) is terete and

slender, with a bilobed stigma (Figure 11-13). The nectary (Figure

II-14A) consists of two large, connate glands positioned adjacent

conniventt) and dorsal to the ovary. Nectar collects within the

corolla at the base of the superior ovary (Lawrence, 1951; Ivanina,

1965; Wiehler, 1979b).



Pollen

The morphology of Codonanthe and Nematanthus pollen is discussed in

CHAPTER V: POLLEN MORPHOLOGY.








Fruit

Fruit type serves as a valuable taxonomic feature in the

infrageneric classification of Codonanthe. Wiehler (1979b) delineates

two subgenera for Codonanthe based upon the type of fruit: a) subgenus

Codonanthe has berries (Figure II-14D) and b) subgenus Codonanthella

has fleshy capsules (Figure II-14E). The berries are globose to

subglobose with pulp consisting of funicular tissue. The fleshy

capsules are laterally compressed and pointed to cone-shaped, bivalved

and loculicidally dehiscent, and have carpel walls that are concave

with reflexed tips. Dehisced capsules split open and display a

cone-shaped mass of funicular tissue, seeds and placentae. Subgenus

Codonanthe is further subdivided by Wiehler (1982 & personal

communication) into sections based upon fruit color: a) section

Codonanthe has orange berries and b) section Spathuliformae has pink,

red or purple berries.

Nematanthus species possess fleshy capsules that are similar to the

fruits of species of Codonanthe subgenus Codonanthella. Wiehler (1979b)

designates this fruit type a "display fruit" and defines it as

a fleshy bivalved capsule with loculicidal dehiscence whose valves
separate at maturity from the placentae which form together with
the mass of seeds and the enlarged, glistening funiculi an
attractively colored cone-shaped structure or food body positioned
upright on the receptacle. The two reflexed or convex carpel
valves are usually strikingly colored on the inside (red, pink,
yellow, or white) to further offset the food body. This display
is surrounded by contrastingly colored calyx lobes which have
grown in size since anthesis. This type of display fruit offers
an outstanding visual target for the seed dispersal agents which
are birds, fruit-eating bats, and possibly monkeys. (p. 69-70)

In summary, the fruit type, color and ability to dehisce appear to

dictate the mode of fruit/seed dispersal. For Codonanthe subgenus

Codonanthe species, orange berries of section Codonanthe and pink, red








and purple berries of section Spathuliformae probably attract and are

disseminated by birds. Fleshy capsules of subgenus Codonanthella

species have the potential to attract birds and ants as the agent of

fruit and seed distribution. The "display fruit" of Nematanthus

species, as previously reported, are most likely dispersed by birds or

fruit-eating bats.



Seed and Seedling

Seeds of Codonanthe and Nematanthus species (Figures II-15 to

II-17) are comparatively large in Gesneriaceae, with such species as C.

calcarata, C. crassifolia, C. macradenia and C. uleana having the

largest gesneriad seeds (Wiehler, 1979b). Seeds range from 1-2 mm long,

occasionally becoming 3.5-3.9 mm long, and are oblong-elliptic in

outline (Ivanina, 1965). The seeds are brown, red, pink or yellow and

longitudinally or obliquely striated (Moore, 1971, 1973a;

Beaufort-Murphy, 1977). Wiehler has estimated that for gesneriaceous

fruit, Codonanthe species probably contain the lowest number of seeds

with between 15 to 125 seeds per berry (35 as an average).

Codonanthe (and probably Nematanthus) seeds are attached to the

placenta via a glistening, hyaline funiculus that is 8-11 mm long and

fleshy (Wiehler, 1979b). A translucent or opaque aril partially (e.g.,

N. gregarius) or entirely (e.g., C. crassifolia) surrounds the seeds

(Moore, 1973a; Beaufort-Murphy, 1977).

Kleinfeldt (1978) and Madison (1979) have reported on the

mutualistic association of a myrmecophyte (C. crassifolia and C.

calcarata) and an ant species (Crematogaster longispina). It appears

that ants are the agents of seed dispersal for C. crassifolia, carrying








seeds to their carton nests. Wiehler (1979b) observed that the seeds

are shaped like ant eggs, perhaps an example of mimicry to aid in seed

dispersal. Ants eat the seed's fleshy aril, as well as the fruit pulp,

and place the seeds in the wall of the nest. The seeds germinate and

C. crassifolia plants grow, and their roots provide the nest with

structural support.





Pollination

Flowers of Codonanthe and Nematanthus species are protandrous

(Moore, 1973a; personal observations), that is, anthers mature and shed

their pollen before stigmas mature and become receptive. This

outbreeding device essentially separates gametes of a flower in time

and to some degree hinders self-fertilization (Allard, 1960). A

species population will usually have many individuals flowering with

flowers at various stages of anthesis.

Anthesis commences with extention and elongation of the filaments

so that the anthers are positioned near the orifice of the corolla

tube. In a nonresupinate flower, connate or connivent anthers are

dorsally located above the corolla throat with the anther pores or

slits shedding pollen downward and inward. Pollen will be deposited on

top of the pollinating agents attracted to the flower. On the second

or third day, the filaments will coil up and retract the anthers into

the flower, removing the source of pollen. The elongating style will

bring the stigma into the former position of the anthers (i.e., above

the corolla throat). The stigma becomes receptive after retraction of

the anthers, removing the opportunity for self-pollination. Pollen








deposited on the dorsal surface of a pollinating agent will be picked

up by the stigma, thus, completing the pollination cycle (Jones & Rich,

1972; Wiehler, 1979b).

In a resupinate flower, the sequence of pollination is similar to

that of a nonresupinate flower except the flower is inverted by 1800.

The anthers and stigma are in a ventral position facing upward, with

pollen shedding and reception occurring on the lower surface of the

pollinating agent. It appears that the pollination sequence is

successful only among nonresupinate and resupinate flowering species,

but not between the two flowering types.

In the pollination of a flower, a complex of characteristics is

exhibited by the flower as a direct result of being adapted to the form

and behavior of the pollinator. Pollination syndromes demonstrate the

conformity between the flowers and the animals which pollinate them

(van der Pijl & Dodson, 1969).

Wiehler (1979b) has estimated that 30% of the Neotropical

gesneriads are pollinated by irridescent male and female Euglossine bees

(gynandro-euglossophily), 60% pollinated by hummingbirds

(ornithophily), and 10% by other biotic agents. Because there is such

a high occurrence of bee- and bird-pollinated flowers among gesneriads,

the syndromes of gynandro-euglossophily and ornithophily were examined.

Flower characters are directly compared with the traits of the

pollinator.

Codonanthe species have 5-merous flowers that are zygomorphic and

held horizontally in the leaf axil. The three corolla lobes are often

enlarged (a possible landing platform), white or yellow in color,

sometimes flushed with yellow, and pink, lilac or deep purple on the









lower surface of the throat (potential nectar guides). Nectar is

contained within a relatively short corolla and/or short spur (nectar

accessible to pollinators with short mouthparts) and anthesis is

diurnal (feeding activity diurnal). These characters appear to fulfill

the syndrome of gynandro-euglossophily flowers.

Tne white, funnel-form corolla of Codonanthe species is very

similar to some corollas of Achimenes, Alsobia, Drymonia, Nautilocalyx

and Sinningia species. Wiehler (1979b) states that these genera are

pollinated by various kinds of female Euglossine bees. Species of

Codonanthe were observed to be visited by Euglossine bees (Williams,

personal communication).

Nematanthus species possess flowers that are tubular or pouched and

held horizontally in or hanging from the leaf axil (pollinator must be

able to hover in front of flower while feeding). Perianth lobes are

curved back or absent (do not interfere with flight movements of the

pollinator), and are scarlet, red, pink, orange or yellow with maroon

stripes (visual sense of the pollinator must be strong). The flower

wall is hard, the filaments are stiff and the corolla tube is broad

(protection from pollinators' hard mouthparts). Nectar is abundant and

stowed away (pollinator must possess long mouthparts to reach the

hidden nectar), and the nectar guides and odor are absent (poor sense

of smell). Anthesis is diurnal (feeding activity diurnal). These

characters appear to fulfill the syndrome of ornithophilous flowers.

Of the four different types of hummingbird corollas present with

Neotropical gesneriads, Wiehler (1979b) reports that the majority of

Nematanthus species have a hypocyrtoid corolla (named after the former








genus Hypocyrta). This corolla type consists of a tube with a ventrally

inflated pouch, tightly constricted throat and narrow limb.

The red, orange and yellow calyx and corolla coloration is a

primary attractant to hummingbirds, but Nematanthus fritschii and N.

maculatus additionally display leaves with a red extrafloral attraction

pattern. The leaves are red-splotched on the abaxial surface. Jones &

Rich (1972) have observed hummingbirds being first attracted to the

foliage of Columnea florida, which possess leaves with "two conspicuous

red spots located on the upper surface near the apex of the large

leaves." Some birds inspected various portions of the plant for

several seconds before finding the flowers.

The function of the inflated pouch of Nematanthus corollas is

unknown. It does not appear to operate as a receptacle for excess

nectar since there are species which have flowers in a nonresupinate

orientation (pouch ventrally located) as well as species with

resupinate flowers (pouch dorsally located). In fact, N. crassifolius

and N. fritschii have pendulous flowers that hang from the leaf axil;

here, a pouch could not function as a nectar receptacle since the

nectar would run out of the flower.

Wiehler (1979b) postulates that the inflated pouch could serve as a

target enlargement. With the hummingbird's approach to the front of the

flower, the pouch contributes to produce a larger target that would aid

in a more effective pollination. The orientation of the flower would

not disrupt this hypothesis since the position of the stamens and

stigma, as discussed, would remain as a functional unit. Also, the

constricted throat of the corolla may serve to exclude larger insects

such as Euglossine bees.








Hummingbird-pollinated flowers frequently have some means of

protecting the ovules. Grant (1950) surveyed the flowering plant

families and examined the relationships between pollinators and any

special means of ovule protection of the flowers they visited. He

observed that Nematanthus (and Hypocyrta) species provided no special

means of ovule protection. In studying Columnea florida (a

hummingbird-pollinated species), Jones & Rich (1972) stated that "the

'V-shaped' nature of the connate anthers and the stigmatic surfaces

(also present in Nematanthus species) serve to direct the bill away

from the superior ovary and into contact with the nectar which collects

in a slight depression in the lower portion of the corolla" (p. 115).



Chromosome Number

Codonanthe and Nematanthus are unique in the tribe Episcieae in

possessing a basic chromosome number of x = 8, whereas all other genera

have a basic chromosome number of x = 9. Table II-1 lists the known

chromosome numbers of Codonanthe and Nematanthus species (Fussell,

1958; Lee, 1962, 1964, 1966; Ratter, 1963; Lee & Grear, 1963; Morley,

1975; Wiehler, 1971, 1975, 1977; Moore, 1973a; Skog, 1980, 1981; Yuen,

personal observation, 1982).

Cultivated species of Nematanthus are diploid (x = 8, n = 8),

whereas Codonanthe has diploid and tetraploid (x = 8, n = 16)

representatives. Species of subgenus Codonanthe section Codonanthe are

diploids, but species of subgenus Codonanthe section Spathuliformae and

subgenus Codonanthella are basically tetraploids; exceptions include C.

caribaea diploidd) and C. luteola diploidd and tetraploid).








Distribution

Species of Codonanthe subgenus Codonanthe section Codonanthe are

confined to the coastal areas of southeastern Brazil. In contrast,

species of subgenus Codonanthe section Spathuliformae and subgenus

Codonanthella inhabit regions from south Mexico, through Central

America, to areas of northern South America--with the southernmost

representatives in Bolivia, Peru and northwestern Brazil. Thus, the

species of this genus have a disjunct distribution.

Nematanthus species are localized in small areas along the coast of

southeastern Brazil as are species of Codonanthe subgenus Codonanthe

section Codonanthe. Species of Nematanthus form a geographically

continuous group with no apparent disjuncts.

A discussion of the implications of geographical distribution to

the taxonomic status of Codonanthe and Nematanthus is presented in

CHAPTER VI: CONCLUSION.







Table II-1. Morphological characteristics of the genera Codonanthe
and Nematanthus.

GROWTH STEM LEAF PETIOLE
TAXA HABIT* SIZE** Shape*** Coloration Size****

GENUS Codonanthe
SUBGENUS Codonanthe
SECTION Codonanthe
1. C. carnosa viny 2-4 round green 4-10
2. C. devosiana viny 2-4 round green 4-10
3. C. digna viny 2-4 round green 4-10
4. C. gracilis viny 2-4 round green 4-10
5. C. paula viny 2-4 round green 4-10
SECTION Spathuliformae
6. C. calcarata vin/shr 2-4 round green 4-10
7. C. corniculata viny 2-4 round red 4-10
8. C. crassifolia viny 2-4 round green 4-10
9. C. uleana vin/shr 2-9 round green 4-10
SUBGENUS Codonanthella
10. C. caribaea vin/shr 2-4 round green 4-10
11. C. chiricana vin/shr 2-4 round green 4-10
12. C. elegans viny 2-4 round green 4-10
13. C. luteola viny 2-4 round green 4-10
14. C. macradenia viny 2-4- round green 4-10


GENUS Nematanthus
1. N. crassifolius shrubby 5-9 rnd/fur green 10-50
2. N. fissus shrubby 5-9 rnd/fur red 10-50
3. N. fritschii shrubby 5-9 round green 10-50
4. N. hirtellus shrubby 5-9 round red 10-50
5. N. maculatus shrubby 5-9 round green 10-50
6. N. perianthomegus shrubby 5-9 round red 10-50

7. N. gregarius viny 2-4 rnd/fur green 4-10
8. N. nervous viny 2-4 rnd/fur green 4-10
9. N. strigillosus viny 2-4 rnd/fur green 4-10
10. N. wettsteinii viny 2-4 round green 4-10




all species are epiphytes, vin/shr=viny/shrubby.
** diameter, in mm.
*** all species possess round petioles, some have a slight furrow on
the adaxial surface of the petiole, rnd/fur=round/furrow.
**** length, in mm.








Table II-1 continued.


Balance*


LEAF BLADE
Form** Apex***


carnosa
devosiana
digna
gracilis
paula

calcarata
corniculata
crassifolia
uleana

caribaea
chiricana
elegans
luteola
macradenia


lam sym/base sym wid ellip
lam sym/base sym wid ellip
lam sym/base sym wid ovate
lam sym/base asym nar ovate
lam sym/base sym wid ovate

lam sym/base asym nar obov
lam sym/base sym wid ellip
lam sym/base sym nar ellip
lam & base asym obovate


1. C.
2. C.
3. C.
4. C.
5. C.

6. C.
7. C.
8. C.
9. C.

10. C.
11. C.
12. C.
13. C.
14. C.


sym elliptic
sym wid obov
sym obovate
sym wid ellip
asym wid ellip


obtuse
acute
obtuse
acute-acum
obtuse

acute
acute
acute-atten
acuminate

attenuate
acute
acute
acute
acute


crassifolius
fissus
fritschii
hirtellus
maculatus
perianthomegus

gregarious
nervous
strigillosus
wettsteinii


lam asym/base sym elliptic
lam sym/base sym elliptic
lam sym/base sym elliptic
lam sym/base sym wid ellip
lam sym/base asym nar obov
lam sym/base sym elliptic

lam sym/base sym wid ellip
lam sym/base asym nar ovate
lam sym/base sym wid ellip
lam sym/base sym wid ellip


acum-atten
acute
acum-atten
acute-obtuse
acum-atten
acute-acum

acute
attenuate
acute
acute


lam=lamina, sym=symmetrical, asym=asymmetrical.
** wid=widely, nar=narrowly, ellip=elliptic, obov=obovate.
*** acum=acuminate, atten=attenuate.
**** obt=obtuse, rnd=rounded.


TAXA


Base****


lam sym/base
lam sym/base
lam sym/base
lam sym/base
lam sym/base


obt-rnd
obt-rnd
rounded
cordate
rounded

cordate
acute
acute
acute


acute
acute
acute
acute
acute


1. N.
2. N.
3. N.
4. N.
5. N.
6. N.

7. N.
8. N.
9. N.
10. N.


acute
acute
acute
obtuse
acute
acute

acute
obt-rnd
acute
acute







Table II-1 continued.


LEAF BLADE
TAXA Margin* Size** Texture


Coloration***


carnosa
devosiana
digna
gracilis
paula

calcarata
corniculata
crassifolia
uleana

caribaea
chiricana
elegans
luteola
macradenia


crassifolius
fissus
fritschii
hirtellus
maculatus
perianthomegus

gregarius
nervous
strigillosus
wettsteinii


sit cren
entire
entire
sit cren
sit cren

crenate
sit cren
entire
sit cren

entire
s1t cren
sit cren
sit cren
sit cren


entire
crenate
entire
entire
entire
slt cren

entire
entire
entire
entire


2-4
2-4
2-4
4-12
2-4

4-12
4-12
4-12
4-12

4-12
2-4
4-12
4-12
4-12


4-12
4-12
4-12
4-12
4-12
4-12

2-4
2-4
2-4
2-4


puberulous
pubescent
puberulous
smooth
puberulous


smooth
smooth
smooth
smooth

smooth
smooth
smooth
smooth
smooth


smooth
pubescent
smooth
puberulous
smooth
smooth

smooth
smooth
pubescent
smooth


red abax leaf surf
green only
red abax leaf surf
red leaf margins
red abax leaf surf

green only
red abax leaf surf
red leaf margins
green only

red leaf margins
green only
red 1 & 20 veins
green only
green only


green only
green only
red 1 & 2
green only
red 10 & 20
green only


veins

veins


green only
green only
red 1 & 20 veins
red lam/green veins


slt cren=slightly crenate.
** length, in cm.
*** all species possess green adaxial leaf surface, coloration pertains
to the abaxial leaf surface besides green, abax=abaxial,
surf=surface, 10 & 2 veins=midrib & secondary veins, lam=lamina.







Table II-1 continued.


FLOWER
TAXA Orientation*


Pedicel**


FLOWER: Calyx
Shape*** Color**** Size**


carnosa
devosiana
digna
gracilis
paula

calcarata
corniculata
crassifolia
uleana

caribaea
chiricana
elegans
luteola
macradenia



crassifolius
fissus
fritschii
hirtellus
maculatus
perianthomegus

gregarius
nervous
strigillosus
wettsteinii


nonresup/erect
nonresup/erect
nonresup/erect
nonresup/erect
nonresup/erect

nonresup/erect
nonresup/erect
nonresup/erect
nonresup/erect

nonresup/erect
nonresup/erect
nonresup/erect
nonresup/erect
nonresup/erect



resup/pendulant
resup/erect
resup/pendulant
resup/erect
resup/erect
resup/erect

nonresup/erect
nonresup/erect
nonresup/erect
nonresup/erect


3-25
3-25
3-25
3-25
3-25

3-25
3-25
3-25
3-25

3-25
3-25
3-25
3-25
3-25



25-200
3-25
25-200
3-25
3-25
3-25


3-25
3-25
3-25
3-25


linear-lanc
linear-lanc
linear-lanc
linear-lanc
linear-lanc

linear-lanc
linear-lanc
linear-lanc
linear-lanc

linear-lanc
linear-lanc
linear-lanc
linear-lanc
linear-lanc



linear-lanc
linear-lanc
linear-lanc
ovate-ellip
ovate-ellip
ovate-ellip

ovate-ellip
ovate-ellip
ovate-ellip
linear-lanc


green
green
green-pur
green-red
green

green
green-red
green
green

green-pur
green-red
green
green-red
green-red



green
green
green-pur
green
green
green


green
green
green
green


nonresup=nonresupinate, resup=resupinate.
** length, in mm.
*** all species possess a 5-parted calyx, shape pertains to calyx lobes,
lanc=lanceolate, ellip=elliptic.
**** pur=purple.


2-10
2-10
2-10
2-10
2-10

2-10
2-10
2-10
2-10

2-10
2-10
2-10
2-10
2-10



10-30
10-30
10-30
10-30
10-30
10-30

10-30
10-30
10-30
10-30







Table II-1 continued.


Shape*


FLOWER: Corolla
Color


carnosa
devosiana
digna
gracilis
paula

calcarata
corniculata
crassifolia
uleana

caribaea
chiricana
elegans
luteola
macradenia


funnelform
funnelform
funnelform
funnelform
funnelform

funnelform
funnelform
funnelform
funnelform

funnelform
funnelform
funnelform
funnelform
funnelform


white
white
white
white
white

white
white
white
white


white +
white +
white +
yellow
white +


yellow, red, brown
brown
pink
yellow, red, purple
pink, red

pink, red, purple
yellow
yellow, pink
yellow, pink, red


yellow,
red
yellow


purple


pink, red


crassifolius
fissus
fritschii
hirtellus
maculatus
perianthomegus

gregarious
nervous
strigillosus
wettsteinii


pouched
pouched
pouched
pouched
pouched
pouched

pouched
pouched
pouched
pouched


red
red
red
yellow
pink +
yellow


4-6
2-4
4-6
2-4
yellow 2-4
+ purple 2-4


orange + yellow
red
orange
orange + yellow


2-4
2-4
2-4
2-4


* all species possess an obliquely ventricose corolla, pouched=Hypocyrta-
type corolla of Wiehler, 1979b.
** length, in cm.


TAXA


Size**


2-4
1-2
1-2
2-4
1-2

2-4
2-4
1-4
2-4

2-4
2-4
2-4
2-4
2-4


TAXA







Table II-1 continued.


FRUIT
TYPE*


POLLINATION CHROMOSOME
AGENT** NUMBER*** DISTRIBUTION****


carnosa
devosiana
digna
gracilis
paula

calcarata
corniculata
crassifolia
uleana

caribaea
chiricana
elegans
luteola
macradenia


indeh/orange
indeh/orange
indeh/orange
indeh/orange
indeh/orange

deh/red-pur
?deh/red-pur
deh/red-pur
deh/red-pur

deh/red-pur
deh/red-pur
deh/yel-grn
deh/yel-grn
deh/red-pur


bee
bee
bee
bee
bee


2n se Brazil
2n se Brazil
se Brazil
2n se Brazil
se Brazil


s Mex-CA-nw
s Mex-CA-nw
s Mex-CA-nw
s Mex-CA-nw


2n s
s
4n s
2n,4n s
4n s


Mex-CA-nw
Mex-CA-nw
Mex-CA-nw
Mex-CA-nw
Mex-CA-nw


crassifolius
fissus
fritschii
hirtellus
maculatus
perianthomegus

gregarious
nervous
strigillosus
wettsteinii


deh/yel-grn
deh/yel-grn
deh/yel-grn
deh/yel-grn
deh/yel-grn
deh/yel-grn

deh/yel-grn
deh/yel-grn
deh/yel-grn
deh/yel-grn


indeh=indehiscent berry, deh=dehiscent, tardily dehiscent or
occasionally splitting berry or fleshy capsule, red-pur=red, purple
or pink, yel-grn=yellow-green.
** bee=euglossine bees, bird=hummingbirds.
*** base chromosome number is x=8, 2n=16 or diploids, 4n=32 or tetraploids.
**** se Brazil=southeastern Brazil, s Mex-CA-nw SA=southern Mexica through
Central America to northwestern South America.


TAXA


bird
bird
bird
bird
bird
bird

bird
bird
bird
bird


Brazil
Brazil
Brazil
Brazil
Brazil
Brazil

Brazil
Brazil
Brazil
Brazil
























Figure II-1. Growth habit of species of Codonanthe subgenus
Codonanthe section Codonanthe.

A. C. carnosa.

B. C. devosiana.

C. C. digna.

D. C. gracilis.

E. C. paula.





33













1A























Figure 11-2. Growth habit of species of Codonanthe subgenus
Codonanthe section Spathuliformae.

A. C. calcarata.

B. C. corniculata.

C. C. crassifolia.

D. C. uleana.

















-4
A..






















Figure 11-3. Growth habit of species of Codonanthe subgenus
Codonanthella.

A. C. caribaea.

B. C. elegans.

C. C. luteola.

D. C. macradenia.





37






















Figure 11-4. Growth habit of species of Nematanthus.

A. N. crassifolius.

B. N. fissus.

C. N. fritschii.

D. N. hirtellus.

E. N. maculatus.

F. N. perianthomegus.





39





















C






















Figure 11-5. Growth habit of species of Nematanthus.

A. N. gregarious.

B. N. nervous.

C. N. strigillosus.

D. N. wettsteinii.






"4




































atD
'All























Figure 11-6. Leaf blade shape of species of Codonanthe subgenus
Codonanthe section Codonanthe.

A. C. carnosa, XI.

B. C. devosiana, XI.

C. C. digna, XI.

D. C. gracilis, XI.

E. C. paula, Xl.



















dif























Figure II-?. Leaf blade shape of species of Codonanthe subgenus
Codonanthe section Spathuliformae.

A. C. calcarata, X1.

B. C. corniculata, X1.

C. C. crassifolia, X1.

D. C. uleana, XI.















I J























Figure 11-8. Leaf blade shape of species of Codonanthe subgenus
Codonanthe.

A. C. caribaea, X1.

B. C. elegans, X1.

C. C. luteola, X1.

D. C. macradenia, X1.




147














A B













C D






















Figure 11-9. Leaf blade shape of species of Nematanthus.

A. N. crassifolius, XI.

B. N. fissus, X1.

C. N. fritschii, XI.

D. N. hirtellus, X1.

E. N. maculatus, Xl.

F. N. perianthomegus, Xl.













I I


IL


c I






















Figure II-10. Leaf blade shape of species of Nematanthus.

A. N. gregarius, XI.

B. N. nervous, Xl.

C. N. strigillosus, Xl.

D. N. wettsteinii, XI.





90


0*























Figure II-11. Floral morphology of species of Nematanthus.

A. N. perianthomegus, side view of resupinate flower with
dorsally-located pouch, X1.5.

B. N. perianthomegus, face view of resupinate flower. Note
anthers within corolla are facing upwards, X6.

C. N. maculatus, side view of resupinate flower with
dorsally-located pouch, X1.5.

D. N. maculatus, face view of resupinate flower. Note
anthers within corolla are facing upwards, X6.

E. N. strigillosus, side view of nonresupinate flower with
ventrally-located pouch, X2.5.

F. N. strigillosus, face view of nonresupinate flower. Note
the stigma of the elongating style moves into the former
dorsal position of the retracting anthers, X11.











L


t






















Figure II-12. Floral morphology of species of Codonanthe.

A. C. luteola, side view of nonresupinate flower with
obliquely funnelform-ventricose corolla, X1.5.

B. C. crassifolia, side view of nonresupinate flower with
obliquely funnelform-ventricose corolla, X3.

C. C. luteola, side view of flower displaying
obliquely-situated corolla within calyx and prominent
spur, X7.

D. C. digna, face view of nonresupinate flower. Note anthers
are dorsally-located within corolla, X8.5.

E. C. macradenia, ventral view of flower depicting a groove
within the corolla, X5.5.

F. C. macradenia, face view of flower depicting a groove
within the corolla, X18.





55









































F























Figure 11-13. Stigma and stigmatic surface.

A. C. devosiana, apical portion of stigma, X120.

B. N. fissus, apical portion of stigma, X71.

C. N. crassifolius, papillae of stigmatic surface, X240.

D. N. fissus, papillae of stigmatic surface, X210.






57

















.*~.JNWg,






















Figure II-14. Floral morphology and fruit of species of
Codonanthe.

A. C. luteola, side view of flower with corolla removed to
reveal gynoecium with a nectary connivent and dorsal to
the ovary, X3.

B. C. corniculata, dorsal view of flower with corolla and
dorsal sepal removed to reveal nectary, X30.

C. C. crassifolia, side view of flower with prominent
extrafloral nectary in the sinus of the calyx lobe
margin, X30.

D. C. crassifolia, side view of subglobose berry, X1.5.

E. C. luteola, side view of pointed capsule, X1.5.






59
































C
,1% ~

'F

--9


I.. ,- -'
p,i,~ -
p~~: :

I5=.























Figure 11-15. Seeds of species of Codonanthe subgenus Codonanthe
section Codonanthe.

A. C. devosiana, X75.

B. C. digna, X75.

C. C. paula, X75.





61























Figure 11-16. Seeds of species of Codonanthe subgenus Codonanthe
section Spathuliformae and subgenus Codonanthella.

A. C. calcarata, X30.

B. C. crassifolia, X50.

C. C. caribaea, X50.

D. C. macradenia, X50.






63


















C D










1/U










b-























Figure 11-17. Seeds of species of Nematanthus.

A. N. gregarius, X75.

B. N. nervous, X75.

C. N. fissus, X75.





65





































C






















Figure 11-18. Seedlings of primary hybrids of Codonanthe and
Nematanthus.

A. Seedlings of C. digna X C. devosiana, X4.

B. Seedlings of N. nervous X N. strigillosus, X2.

C. Seedlings of N. strigillosus X C. carnosa, X4.

D. Seed germinating container with C. digna X C. paula
seedlings, X1/3.





67





aa










to

AC1



w\














CHAPTER III
COMPARATIVE MORPHOLOGY OF THE LEAF EPIDERMIS


Introduction

The taxonomic value of the morphology of leaf epidermal surfaces

has been expounded by Stace (1965) and Sinclair & Sharma (1971).

Conventional light microscopy (LM) methods of examining Gesneriaceae

leaf surfaces have been used in the study of the genera Columnea and

Alloplectus (Steam, 1969), Gesneria (Skog, 1976), and in some

gesneriads of Africa and Asia (Sahasrabudhe & Stace, 1974), Sri Lanka

(Herat & Theobald, 1979) and the Neotropics (Wiehler, 1979b).

Taxonomic investigations utilizing scanning electron microscopy (SEM)

have been relatively limited. Some recent SEM studies include those of

Atwood & Williams (1979) for Cypripedioideae (Orchidaceae), Thomson &

Mohlenbrock (1979) for Quercus (Fagaceae), Hardin (1979, 1981) for some

North American woody plants, Dehgan (1980) for Jatropha (Euphorbiaceae)

and Rudall (1980) for Hyptis (Labiatae). However, the comparative

morphology of Gesneriaceae leaf epidermis utilizing SEM has not been

reported. This study of leaf surfaces was initiated to discover more

characters of taxonomic utility in evaluating the subgeneric categories

of Codonanthe and to establish natural groupings in Nematanthus.



Materials and Methods

All plant materials examined were from a live collection

cultivated in a growth room at the Department of Ornamental









Horticulture, University of Florida. Uniform conditions were

maintained via a 22-250 C day temperature, 17-20 C night temperature,

4000-6000 Lux fluorescent lighting and a 14 hour daylength. Voucher

specimen are deposited at the University of Florida herbarium (FLAS).

In the SEM preparation (cf., Hayat, 1978), mature leaves were

sampled using a no. 2 cork borer to punch out 5 mm leaf discs which

were fixed overnight in 2% glutaraldehyde. Leaf samples were then

dehydrated in a 20-100% ethanol series for 2 hours, critical point

dried for 30 minutes, mounted on aluminum stubs with TV Tube Koat (GC

Electronics), and coated with a gold-palladium mixture. A Hitachi

S-450 Scanning Electron Microscope was used to view the specimens and

photographs were recorded on Polaroid Type 55 Positive/Negative film.

In the LM preparation, immature and mature leaves were sampled for

ontogenetic studies of the stomata and the examination of leaf surfaces,

respectively. Free-hand paradermal sections were taken with a razor

blade and mounted in water for observation. Guard cell length and

width were measured with an eyepiece micrometer and presented as a mean

value + the standard error of the mean (x + S.E.x). A guard cell area

index was calculated by multiplying the mean length by the mean width

of the guard cells. A Wild M-20EB Light Microscope was used to examine

the specimens.



Observations

Descriptive terminology of epidermal features is based on Dilcher

(1974) and summarized in Table III-1. Definitions of terms used in the

text are briefly reviewed below.









Trichomes. Glandular and nonglandular trichomes can be recognized

on the adaxial and abaxial leaf surface. Nonglandular trichomes may be

unicellular or multicellular-uniseriate. Glandular trichomes are

multicellular and composed of a head and a body. The head consists of

2, 4 or more cells and the body is either short or long (cf., Esau,

1965). Short glandular trichomes have a unicellular body while long

(stalked) glandular trichomes have a multicellular-uniseriate body.

Basal cells of glandular trichomes may be randomly-arranged,

radially-arranged or sunken. The sunken basal cell type gives the

glandular head a sessile appearance, as though it were attached

directly to the epidermis with no basal trichome cell (Sahasrabudhe &

Stace, 1974; Wiehler, 1979b).

Stomata. Anisocytic and helicocytic stomata have been observed on

the abaxial leaf surface. Anisocytic stomata have guard cells

surrounded by three unequal subsidiary cells of which one is distinctly

smaller than the other two. Helicocytic stomata have guard cells

surrounded by four or more subsidiary cells arranged in a helix

(Fryns-Claessens & Van Cotthem, 1973).

Extrafloral Nectaries. These are nectaries (distinct from

glandular trichomes) that appear other than on the flower (Moore,

1973a). In the plants studied here they occur on the abaxial surface

of the leaf. These extrafloral nectaries are composed of a central

area where the epidermal cells form a pigmented swelling in the leaf

surface and a surrounding area which is encircled with short glandular


trichomes.









Epidermal Cells. Epidermal cell surfaces are rather smooth or

contain surface ornamentations in the form of echinate papillae or

striations (Dilcher, 1974).



GENUS Codonanthe (Martius) Hanstein

Several leaf epidermal features were consistent in all species of

Codonanthe. Epidermal cells were isodiametric and randomly-arranged.

Stomata occurred abaxially and were randomly distributed. Surface

ornamentations were not evident on subsidiary or guard cells and all

cells were topographically at the same level.

SUBGENUS Codonanthe

Nine known species of this subgenus were examined.

SECTION Codonanthe. Five species were studied (Figures III-1A to

III-iF): C. carnosa (Gardner) Hanstein, C. devosiana Lem., C. digna

Wiehler, C. gracilis (Martius) Hanstein, and C. paula Wiehler.

Multicellular-uniseriate nonglandular trichomes, occurring on both

leaf surfaces (except abaxially only in C. gracilis), had basal

epidermal cells radially-arranged (except randomly-arranged in C.

gracilis). Multicellular glandular trichomes, present on both leaf

surfaces, had a 4-celled head, a short (unicellular) body and

randomly-arranged basal epidermal cells (except basal cell sunken in C.

gracilis). Anisocytic stomata were observed on the abaxial leaf

surface. Extrafloral nectaries were absent. No surface ornamentations

were evident, except in C. gracilis which had epidermal cells with

echinate papillae. Guard cells had a mean length of 23.2um, mean width

of 19.7um and area index of 458um2.









SECTION Spathuliformae L. B. Smith. Four species were examined

(Figures III-2A, III-2C, III-3A to III-3D): C. calcarata (F. A. W.

Miquel) Hanstein, C. corniculata Wiehler, C. crassifolia (Focke) Morton

and C. uleana Fritsch.

Unicellular nonglandular trichomes, present on both leaf surfaces,

had randomly-arranged basal epidermal cells. Multicellular glandular

trichomes, also present on both leaf surfaces, had a 2-celled head, a

short (unicellular) body and randomly-arranged basal epidermal cells.

Anisocytic stomata and extrafloral nectaries were present on the

abaxial leaf surface. No surface ornamentations were evident. Guard

cells had a mean length of 30.3um, mean width of 26.2um and area index

of 796um2

SUBGENUS Codonanthella Wiehler

Five species in this subgenus were examined (Figures III-2B,

III-2D to III-2F): C. caribaea Urban, C. chiricana Wiehler, C. elegans

nomen nudum (to be described by Wiehler, 1982), C. luteola Wiehler and

C. macradenia Donnell-Smith.

Unicellular nonglandular trichomes, present on both leaf surfaces

(except abaxially-occurring multicellular trichomes of C. caribaea), had

randomly-arranged basal epidermal cells. Multicellular glandular

trichomes, present on both leaf surfaces, had a 2-celled head (except

4-celled in C. caribaea) and a short (unicellular) body. Basal

epidermal cells were randomly-arranged (except basal cell sunken in C.

caribaea). Anisocytic stomata and extrafloral nectaries were present

on the abaxial leaf surface in C. chiricana, C. elegans, C. luteola and

C. macradenia but not in C. caribaea. No surface ornamentations were

evident except in C. caribaea which had epidermal cells with echinate








papillae. Guard cells had a mean length of 33.1um, mean width of

28.2um and area index of 936um2.



GENUS Nematanthus Schrader

Several leaf epidermal features were consistent in all species of

Nematanthus. Epidermal cells were isodiametric and randomly-arranged.

Stomata were abaxially occurring and randomly oriented. No surface

ornamentations were evident on subsidiary and guard cells, and all

cells were topographically at the same level.

Ten species placed in this genus were examined (Figures III-4A to

III-6F): N. crassifolius (Schott) Wiehler, N. fissus (Vellozo) L. Skog,

N. fritschii Hoehne, N. gregarious D. Denham, N. hirtellus (Schott)

Wiehler, N. maculatus (Fritsch) Wiehler, N. nervous (Fritsch) H. E.

Moore, N. perianthomegus (Vellozo) H. E. Moore, N. strigillosus

(Martius) H. E. Moore and N. wettsteinii (Fritsch) H. E. Moore.

Multicellular-uniseriate nonglandular trichomes with

radially-arranged basal epidermal cells occurred in all species.

Multicellular glandular trichomes with a 4-celled head and only one

trichome per basal epidermal cell, a short (unicellular) or long

(multicellular) body, and anisocytic stomata were characteristic of N.

crassifolius, N. fissus, N. fritschii, N. hirtellus, N. maculatus and

N. perianthomegus. Multicellular glandular trichomes with a

4-or-more-celled head and/or more than one trichome per basal epidermal

cell, a short (unicellular) body, and helicocytic and anisocytic

stomata were characteristic of N. gregarius, N. nervous, N.

strigillosus and N. wettsteinii. The occurrence of nonglandular

trichomes varied among Nematanthus species while glandular trichomes







Table III-1. Leaf epidermal characters of Codonanthe and Nematanthus.

NONGLANDULAR TRICHOMES

Number Basal Epidermal
Occurrence of Cells Cell Arrangement

AB=abaxial l=unicellular
AD=adaxial #=multicellular
TAXON -uniseriate


GENUS Codonanthe

SUBGENUS Codonanthe

SECTION Codonanthe
C. carnosa AB + AD # radial
C. devosiana AB + AD # radial
C. digna AB + AD # radial
C. gracilis AB # random
C. paula AB + AD # radial

SECTION Spathuliformae
C. calcarata AB + AD 1 random
C. corniculata AB + AD 1 random
C. crassifolia AB + AD 1 random
C. uleana AB + AD 1 random

SUBGENUS Codonanthella
C. caribaea AB # random
C.- chiricana AB + AD 1 random
C. elegans AB + AD 1 random
C. luteola AB + AD 1 random
C. macradenia AB + AD 1 random


GENUS Nematanthus
N. crassifolius AB # radial
N. fissus AB + AD # radial
N. fritschii AB # radial
N. hirtellus AB + AD # radial
N. maculatus AB # radial
N. perianthomegus AB + AD # radial

N. gregarius absent ---
N. nervous AB + AD # radial
N. strigillosus AB + AD # radial
N. wettsteinii AB # radial








Table III-1 continued.

GLANDULAR TRICHOMES1

Glandular Basal Epidermal 3
Head Body Cell Arrangement

S=short unicellular
L=long multicellular
TAXON


GENUS Codonanthe

SUBGENUS Codonanthe

SECTION Codonanthe
C. carnosa 4-celled S unmodified
C. devosiana 4-celled S unmodified
C. digna 4-celled S unmodified
C. gracilis 4-celled S modified
C. paula 4-celled S unmodified

SECTION Spathuliformae
C. calcarata 2-celled S unmodified
C. corniculata 2-celled S unmodified
C. crassifolia 2-celled S unmodified
C. uleana 2-celled S unmodified

SUBGENUS Codonanthella
C. caribaea 4-celled S modified
C. chiricana 2-celled S unmodified
C. elegans 2-celled S unmodified
C. luteola 2-celled S unmodified
C. macradenia 2-celled S unmodified


GENUS Nematanthus
N. crassifolius 4-celled S or L modified
N. fissus 4-celled S or L modified
N. fritschii 4-celled S or L modified
N. hirtellus 4-celled S or L modified
N. maculatus 4-celled S or L modified
N. perianthomegus 4-celled S or L modified

N. gregarius >4-celled2 S modified
N. nervous >4-celled S modified
N. strigillosus >4-celled S modified
N. wettsteinii >4-celled S modified

1 Occurs on both surfaces of the leaves in all species.
2 More than 4 cells per head and/or more than 1 trichome per basal
epidermal cell.
3 Unmodified=randomly-arranged; modified=trichomes with a unicellular
body have a sunken epidermal cell while trichomes with a multicellular
stalked body have radially-arranged epidermal cells.







Table III-1 continued.


STOMATA
TYPE


EPIDERMAL CELL
ORNAMENTATION


AN=anisocytic
HEL=helicocytic


GENUS Codonanthe

SUBGENUS Codonanthe


SECTION Codonanthe
C. carnosa
C. devosiana
C. digna
C. gracilis
C. paula

SECTION Spathuliformae
C. calcarata
C. corniculata
C. crassifolia
C. uleana

SUBGENUS Codonanthella
C. caribaea
C. chiricana
C. elegans
C. luteola
C. macradenia


GENUS Nematanthus
N. crassifolius
N. fissus
N. fritschii
N. hirtellus
N. maculatus
N. perianthomegus

N. gregarius
N. nervous
N. strigillosus
N. wettsteinii


AN
AN
AN
AN
AN
AN

+ HEL
+ HEL
+ HEL
+ HEL


absent
absent
absent
absent
absent


abaxial
abaxial
abaxial
abaxial


absent
abaxial
abaxial
abaxial
abaxial



absent
absent
absent
absent
absent
absent

absent
absent
absent
absent


none
none
none
echinate papillae
none


none
none
none
none


echinate papillae
none
none
none
none


none
striations
none
none
none
none

none
none
none
striations


TAXON


EXTRAFLORAL
NECTARY








were situated abaxially only. Glandular trichomes had modified basal

epidermal cells, i.e., trichomes with a unicellular body had a sunken

basal epidermal cell while trichomes with a multicellular body had

radially-arranged basal epidermal cells. Extrafloral nectaries and

surface ornamentations were absent, except for striations on epidermal

cells in N. fissus and N. wettsteinii. Guard cells had a mean length

of 29.5um, mean width of 22.5um and area index of 666um2.



Discussion

Although features of the adaxial and abaxial surfaces of the

leaves are consistent within sections of genus Codonanthe, differences

are noted among sections in subgenus Codonanthe. Species of subgenus

Codonanthe section Spathuliformae share more epidermal characters with

species in subgenus Codonanthella than with those species in subgenus

Codonanthe section Codonanthe. Multicellular-uniseriate nonglandular

trichomes (Figures III-1A & III-1B) with radially-arranged basal

epidermal cells (Figure III-1C), glandular trichomes with 4-celled

heads (Figure III-1D), and the absence of extrafloral necteries are

consistent characters in species of section Codonanthe. Species in

section Spathuliformae and subgenus Codonanthella share certain

epidermal characters which include unicellular glandular trichomes

(Figures III-2A & III-2B) with randomly-arranged basal epidermal cells,

multicellular glandular trichomes with 2-celled heads (Figures III-2C &

III-2D), and the presence of extrafloral nectaries (except in C.

caribaea; Figures III-3A & III-3D).

Codonanthe gracilis and C. caribaea (Figure III-2F) have been

placed in different subgenera (Wiehler, 1982), but are identical in all









leaf epidermal characters. For example, both species possess

multicellular-uniseriate nonglandular trichomes, multicellular glandular

trichomes with a 2-celled head and a short (unicellular) body,

anisocytic stomata and epidermal cells with echinate papillae.

Codonanthe caribaea also shares some epidermal characters with the

section Codonanthe.

Kleinfeldt (1978) and Madison (1979) described the mutualistic

association between Codonanthe crassifolia, C. calcarata and C. uleana

and tropical arboreal ants. Ants are the agents of seed dispersal,

carrying Codonanthe seeds to their carton nests. The seeds germinate

and penetrate the carton with fibrous roots. The roots function as a

framework, providing the ant nests with structural support. Codonanthe

plants furnish food to the ants in the form of floral and extrafloral

nectar, fruit pulp and seed arils. Kleinfeldt (1978) observed that the

major food source for the ants is the nectar of Codonanthe.

Extrafloral nectaries are located on the abaxial leaf surface and occur

in species of subgenus Codonanthe section Spathuliformae and subgenus

Codonanthella, but are absent in species of subgenus Codonanthe section

Codonanthe. The presence of foliar extrafloral nectaries in Codonanthe

species appears to be associated with the occurrence of an ant-plant

mutual ism.

Species of Nematanthus exhibit similar leaf epidermal features, but

differ with respect to the type of glandular trichomes and stomata. In

N. gregarius, N. nervous, N. strigillosus and N. wettsteinii,

glandular trichomes have a head of more than 4 cells (Figures III-6D to

III-6F) and/or more than one trichome per basal epidermal cell (Figure

III-4D). The capacity for secretion appears to be greater in these four








species, when compared to the six species of Nematanthus, perhaps due

to the greater number of cells in the head of the glandular trichomes.

Although N. gregarius has only a 4-celled glandular head, two or more

glandular trichomes occur in a single locale and this arrangement may

increase the potential of secretion by compensating for the 4-celled

condition with more secreting heads.

The anisocytic type of stomata (Figure III-5C) is present in all

species of Nematanthus, whereas the anisocytic and helicocytic stomatal

types (Figure III-5D) occur in N. gregarius, N. nervous, N.

strigillosus and N. wettsteinii. The occurrence of two stomatal types

in one species is unusual, however, the anisocytic and helicocytic

stomatal types are derived from the same developmental sequence (Payne,

1970 and personal observation), so their occurrence together might not

be unexpected. The stomatal initial forms only three subsidiary cells

in the anisocytic stomatal type but continues to divide forming four or

more subsidiary cells in a helix in the helicocytic type of stomata.

Since guard cells and subsidiary cells originate from the same stomatal

initial, the developmental sequence is referred to as mesogenous

(Fryns-Claessens & Van Cotthem, 1973) or eumesogenous (Stevens &

Martin, 1978). Stomatal types in Nematanthus, therefore, are

classified ontogenetically as aniso-mesogenous or aniso-eumesogenous,

and helico-mesogenous or helico-eumesogenous.

Guard cell area indices are calculated to provide a value

representative of guard cell size, allowing a comparison among taxa.

Subgenus Codonanthe section Spathuliformae (area index 796um2) have

guard cells that are more similar in size with subgenus Codonanthella

(area index 936um2 ) than with subgenus Codonanthe section Codonanthe








(area index 458um2). Wiehler (1975) reported that species of subgenus

Codonanthe section Codonanthe are diploids (n=8) while species of

subgenus Codonanthe section Spathuliformae and subgenps Codonanthella

are tetraploids (n=16), except C. caribaea diploidd) and C. luteola

diploidd and tetraploid). The larger size of the guard cells of the

tetraploid species is apparently related to the gigas effect of

polyploidy (Stebbins, 1971).

Species of Nematanthus are diploids (n=8; Skog, 1981) and have a

guard cell area index of 666um2 This area index is intermediate

between area indices of diploid and tetraploid species of Codonanthe.

Nematanthus species appear to be distinct from species of Codonanthe

with respect to guard cell dimensions and ploidy level.

Nematanthus species share many epidermal characters with species in

subgenus Codonanthe section Codonanthe (including

multicellular-uniseriate nonglandular trichomes) and only a few

characters with species of subgenus Codonanthe section Spathuliformae

and subgenus Codonanthella. Morphological similarities in the epidermal

surfaces of the leaves in subgenus Codonanthe section Codonanthe and

Nematanthus are either an ancestral feature shared by the two genera,

or are the result of parallel evolution related to a similarity of

ecogeographical conditions.























Figure III-1. Leaf epidermal features of species of Codonanthe
subgenus Codonanthe section Codonanthe.

A. C. paula, multicellular nonglandular and glandular
trichomes, X100.

B. C. digna, multicellular nonglandular and glandular
trichomes, X250.

C. C. carnosa, radially-arranged basal epidermal cells of
nonglandular trichomes, X1000.

D. C. gracilis, 4-celled head of glandular trichome, X1650.

E. C. gracilis, echinate papillae and stoma, X1000.

F. C. devosiana, anisocytic stoma, X1500.







































39V


S
~=i





"~D


I Uj


'i
.4






















Figure III-2. Leaf epidermal features of species of Codonanthe
subgenus Codonanthe section Spathuliformae and subgenus
Codonanthella.

A. C. crassifolia, unicellular nonglandular trichome, X1000.

B. C. elegans, unicellular nonglandular trichome, X1200.

C. C. calcarata, 2-celled head of glandular trichome, X2000.

D. C. luteola, 2-celled head of glandular trichome, X1120.

E. C. macradenia, anisocytic stoma, X1260.

F. C. caribaea, multicellular nonglandular trichome and
sunken epidermal cell of glandular trichome, X350.













hA "
,'i 10





pi a
I, "*? <























Figure III-3. Leaf epidermal features of species of Codonanthe
subgenus Codonanthe section Spathuliformae.

A. C. crassifolia, extrafloral nectary, X100.

B. C. uleana, extrafloral nectary, X150.

C. C. uleana, glandular trichomes that encircle extrafloral
nectary, X1000.

D. C. corniculata, extrafloral nectary, X110.


























mbrig
-ft F^ -.


5~~ WLa~- pP qw
s'r bsLs-Im
yfy^'ss D





















Figure 11-4. Leaf epidermal features of species of Nematanthus.

A. N. fissus, multicellular nonglandular trichome, X110.

B. N. strigillosus, multicellular nonglandular trichome, X500.

C. N. perianthomegus, glandular trichome with short
(unicellular) and long (multicellular) body cells, X500.

D. N. strigillosus, 2 short glandular trichomes per single
basal epidermal cell, X400.











83






















Figure 111-5. Leaf epidermal features of species of Nematanthus.

A. N. hirtellus, glandular trichome with bicellular body,
X100o.

B. N. wettsteinii, glandular trichome, stomata and striated
epidermis, X500.

C. N. crassifolius, anisocytic stoma, X1330.

D. N. gregarius, helicocytic stoma, X1230.











I-


If (


b


t .~






















Figure III-6. Leaf epidermal features of species of Nematanthus.

A. N. fissus, 4-celled head of glandular trichome, X500.

B. N. nervous, 6-celled head of glandular trichome, X2000.

C. N. hirtellus, 4-celled head of glandular trichome, X500.

D. N. wettsteinii, 8-celled head of glandular trichome, X1400.

E. N. maculatus, unicellular basal epidermal cell of
glandular trichome, X1450.

F. N. wettsteinii, unicellular basal epidermal cell of
glandular trichome, X1300.




92











m
A













LE














CHAPTER IV
COMPARATIVE ANATOMY OF THE STEM AND LEAF


Introduction

Anatomical studies of Codonanthe and Nematanthus are restricted to

plants considered in Wiehler's (1970, 1979b, 1982) taxonomic treatment

of the Neotropical Gesneriaceae, where node, petiole and leaf structure

were described for some species. Related anatomical studies are

presented by Skog (1976) for the genus Gesneria, Jong & Burtt (1975)

for the genus Streptocarpus, Herat & Theobald (1979) for various

gesneriad species of Sri Lanka, Rosser & Burtt (1969) for the tribe

Trichosporeae, and Solereder (1908) and Metcalfe & Chalk (1950) for

various species of Gesneriaceae. Nodal and wood anatomy were discussed

by Howard (1970) for the genus Alloplectus, and Bierhorst (1964), Chalk

(1937), Sinnott (1914) and Sinnott & Bailey (1914) for Gesneriaceae.

Bokhari & Burtt (1970) and Burtt & Bokhari (1973) described foliar

sclereids in gesneriads of the Old World. This preliminary study of

stem and leaf anatomy of Codonanthe and Nematanthus species was

initiated to disclose more taxonomically useful characters.



Materials and Methods

Live specimens of all known cultivated species of Codonanthe and

Nematanthus were examined. Plant materials were cultivated in a growth

room at the Department of Ornamental Horticulture, University of

Florida. The growth room provided uniform conditions of 22-25C day








temperature, 17-2'0 C night temperature, 4000-6000 Lux fluorescent

lighting and a fourteen hour daylength. Voucher specimens were

deposited at the University of Florida herbarium (FLAS).

Mature portions of nodes and internodes, petioles and blades were

collected. Freehand serial sections of fresh material were stained

with and mounted in toluidine blue 0 (Sakai, 1973; Dehgan, 1982).

Microtome serial sections of paraffin-embedded material were stained

with toluidine blue 0 and safranin-fast green (Berlyn & Miksche, 1976)

and mounted in Permount (Fisher Scientific Company). Specimens were

examined with a Wild M-20EB Light Microscope.

The leaf clearing method of Shobe & Lersten (1967) was utilized

for the study of leaf architecture. All steps were followed except

chloral hydrate was omitted and only safranin 0 stain was used.

Terminology employed for describing the leaf venation patterns is based

upon Hickey's (1973) classification of the architecture of

dicotyledonous leaves. Specimens were examined with a Wild M8 Zoom

Stereomicroscope.



Observations

Stem Anatomy

The epidermis consisted of a single layer of tabular cells (rarely

2-3 cells thick). The cuticle was thin, and glandular and nonglandular

trichomes were randomly situated around the stem. The cortex and pith

were composed of chlorenchyma of basically isodiametric cells among

which were many intercellular spaces or cells were irregularly-shaped

with few intercellular spaces (i.e., cells tightly appressed to each

other). Druses were often present in cortex cells, whereas prismatic




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