The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
site maintained by the Florida
Cooperative Extension Service.
Copyright 2005, Board of Trustees, University
Bulletin 510 December 1952
(A Revision of Bulletin 468)
UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
WILLARD M. FIFIELD, Director
Poisonous Plants in Florida
ERDMAN WEST and M. W. EMMEL
Fig. 1.-Cocklebur-fruiting branch and three seedlings.
BOARD OF CONTROL EDITORIAL
J. Francis Cooper, M.S.A., Editor
Frank M. Harris, Chairman, St. Petersburg Clyde Beale, A.B.J., Associate Editor
Hollis Rinehart, Miami L. Odell Griffith, B.A.J., Asst. Editor
Eli H. Fink, Jacksonville J. N. Joiner, B.S.A., Assistant Editor 8
George J. White, Sr., Mount Dora William G. Mitchell, A.B.J., Assistant Editor
Mrs. Alfred I. duPont, Jacksonville
George W. English, Jr., Ft. Lauderdale ENTOMOLOGY
W. Glenn Miller, Monticello
W. F. Powers, Secretary, Tallahassee A. N. Tissot, Ph.D., Entomologist1
L. C. Kuitert, Ph.D., Associate
EXECUTIVE STAFF H. E. Bratley, M.S.A., Assistant
F. A. Robinson, M.S., Asst. Apiculturist
J. Hlis Miller, Ph.D., Presidentr R. E. Waites, Ph.D., Asst. Entomologist
J. Wayne Beltz, Ph.D., Provost for Agr.5
Willard M. Fifield, M.S., Director
J. R. Beckenbach, Ph.D., Asso. Director HOME ECONOMICS
L. O. Gratz, Ph.D., Assistant Director Ouida D. Abbott, Ph.D., Home Econ.1
Rogers L. Bartley, B.S., Admin. Mgr.s R. B. French, Ph.D., Biochemist
Gee. R. Freeman, B.S., Farm Superintendent
MAIN STATION, GAINESVILLE G. H. Blackmon, M.S.A., Horticulturist1
F. S. Jamison, Ph.D., Horticulturist 84
AGRICULTURAL ECONOMICS Albert P. Lorz, Ph.D., Horticulturist
H. G. Hamilton, Ph.D., Agr. Economist K. Showalter, M.S., Asso. Hort.
. E.G. eHamlton, Ph.D., Agr. Economist R. A. Dennison, Ph.D., Asso. Hort.
R. E. L. Greene, Ph.D., Agr. Economist R. H. Sharpe, M.S., Asso. Horticulturist
M. A. Brooker, Ph.D., Agr. Economist' V. F. Nettles, Ph.D., Asso. Horticulturist
Zach Savage, M.S.A., Associate F. S. Lagasse, Ph.D., Asso. Hort.
A. Spurleek, M.S.A., Associate R. D. Dickey, M.S.A., Asso. Hort.
D. E. Alleger, M.S., Associate L. H. Halsey, M.S.A., Asst. Hort.
D. L. Brooke, M.S.A., Associate 3 C. B. Hall, Ph.D., Asst. Horticulturist
. R. Godwin, Ph.D., Associate Austin Griffiths, Jr., B.S., Asst. Hort.
H. W. Little, M.S., Assistant S. E. McFadden, Jr., Ph.D., Asst. Hort.
W. K McPherson, M.S., Economist C. H. VanMiddelem, Ph.D., Asst. Biochemist
Eric Thor, M.S., Asso. Agr. Economist Buford Thompson, M.S.A., Asst. Hort.
J. L. TennSnt, Ph. ., Agr. Economist James Montelaro, Ph.D., Asst. Horticulturist
Cecil N. Smith, M.A., Asso. Agr. Economist
Levi A. Powell, Sr., M.S.A., Assistant LIBRARY
Orlando, Florida (Cooperative USDA) Ida Keeling Cresap, Librarian
G. Norman Rose, B.S., Asso. Agri. Economist
J. C. Townsend, Jr., B.S.A., Agricultural PLANT PATHOLOGY
Statistician W. B. Tisdale, Ph.D., Plant Pathologist 1
J. B. Owens, B.S.A., Agr. Statistician s Phares Decker, Ph.D., Plant Pathologist
J. K. Lankford, B.S., Agr. Statistician Erdman West, M.S., Mycologist and
AGRICULTURAL ENGINEERING Robert W. Earhart. Ph.D., Plant Path.2
Frazier Rogers, M.S.A., Agr. Engineer13 Howard N. Miller, Ph.D., Asso. Plant Path.
J. M. Johnson, B.S.A.E., Agr. Eng.8 Lillian E. Arnold, M.S., Asst. Botanist
J. M. Myers, B.S., Asso. Agr. Engineer C. W. Anderson, Ph.D., Asst. Plant Path.
J. S. Norton, M.S., Asat. Agr. Eng.
AGRONOMY N. R. Mehrhof, M.Agr., Poultry Husb.1'
Fred H. Hull, Ph.D., Agronomist 2 J. C. Driggers, Ph.D., Asso. Poultry Hush.
G. B. Killinger, Ph.D., Agronomist
H. C. Harris, Ph.D., Agronomist SOILS
R. W. Bledsoe, Ph.D., Agronomist F. B. Smith, Ph.D., Microbiologist 1
W. A. Carver, Ph.D., Associate Gaylord M. Volk, Ph.D., Soils Chemist
Darrel D. Morey, Ph.D., Associate J. R. Neller, Ph.D., Soils Chemist
Fred A. Clark, M.S., Assistant Nathan Gammon, Jr., Ph.D., Soils Chemist
Myron C. Grennell, B.S.A.E., Assistant Ralph G. Leighty. B.S., Asst. Soil Surveyor
E. S. Horner, Ph.D., Assistant G. D. Thornton, Ph.D., Asso. Microbiologist
A. T. Wallace, Ph.D., Assistant8 Charles F. Eno, Ph.D., Asst. Soils Micro-
D. E. McCloud, Ph.D., Assistant' biologist 4
E. C. Nutter, Ph.D., Asst. Agronomist H. W. Winsor, B.S.A., Assistant Chemist
ANIMAL HUSBANDRY AND NUTRITION R. E. Caldwell, M.S.A., Asst. Chemists84
ANIMAL HUBANDRY AND NUTRITION W. Carlisle, B.S., Asst. Soil Surveyor
T. J. Cunha, Ph.D., An. Husb.1 J. H. Walker, M.S.A., Asst. Soil Surveyor
G. K. Davis, Ph.D., Animal Nutritionist s S. N. Edson, M. S., Asst. Soil Surveyor
S. John Folks, Jr., M.S.A., Asst. An. Hush. William K. Robertson, Ph.D., Asst. Chemist
Katherine Boney, B.S., Asst. Chem. O. E. Cruz, B.S.A., Asst. Soil Surveyor
A. M. Pearson, Ph.D., Asso. An. Husb.8 W. G. Blue, Ph.D., Asst. Biochemist
John P. Feaster, Ph.D., Asst. An. Nutri. J. G. A. Fiskel, Ph.D., Asst. Biochemist
I. D. Wallace, Ph.D., Asst. An. Hush. a H. F. Ross, B.S., Soils Microbiologist
M. Koger, Ph.D., An. Husbandman 3 L. C. Hammond, Ph.D., Asst. Soil Physicist
E. F. Johnston, M.S., Asst. An. Husbandman H. L. Breland, Ph.D., Asst. Soils Chem.
J. F. Hentges, Jr., Ph.D., Asst. An. Hush.
DAIRY SCIENCE D. A. Sanders, D.V.M., Veterinarian
E. L. Fouts, Ph.D., Dairy Tech. 3 M. W. Emmel, IY.V.M., Veterinarian $
R. B. Becker, Ph.D., Dairy Husb.3 C. F. Simpson, D.V.M., Asso. Veterinarian
S. P. Marshall, Ph.D., Asso. Dairy Husb.3 L. E. Swanson, D.V.M., Parasitologist
W. A. Krienke, M.S., Asso. Dairy Tech.8 Glenn Van Ness, D.V.M., Asso. Poultry
P. T. Dix Arnold, M.S.A., Asst. Dairy Husb.' Pathologist
Leon Mull, Ph.D., Asso. Dairy Tech. W. R. Dennis, D.V.M.. Asst. Parasitologist
H. H. Wilkowske, Ph.D., Asst. Dairy Tech. E. W. Swarthout, D.V.M., Poultry
James M. Wing, M.S., Asst. Dairy Hush. Pathologist
BRANCH STATIONS SUS-TROPICAL STATION, HOMESTEAD
Gee. D. Ruehle, Ph.D., Vice-Dir. in Charge
NORTH FLORIDA STATION, QUINCY D. Wolenbarger, Ph.D., Entomologist
Francis B. Lincoln, Ph.D., Horticulturist
W. C. Rhoades, Jr., M.S., Entomologist in Robert A. Conover, Ph.T., Plant Path.
Charge John L. Malcolm, Ph.D., Asso. Soils Chemist
R. R. Kincaid, Ph.D., Plant Pathologist W. Harkness, Ph.D., Asst. Chemist
L. G. Thompson, Jr., Ph.D., Soils Chemist R. Bruce Ledin, Ph.D., Asst. Hort.
W. H. Chapman, M.S., Asso. Agronomist J C. Noonan, M.S., Asst. Hort.
Frank S. Baker, Jr., B.SA Asst. An. Hush. M. H. Gallatin, B.S., Soil Conservationist
T. E. Webb, B.S.A., Asst. Agronomist
Frank E. Guthrie, Ph.D., Asst. Entomologist
Mobile Unit, Monticello WEST CENTRAL FLORIDA STATION,
R. W Wallace, B.S., Associate Agronomist BROOKSVILLE
Mobile Unit, Marianna Marion W. Hazen, M.S., Animal Husband-
R. W. Lipscomb, M.S., Associate Agronomist man in Charge 2
Mobile Unit, Pensacola
R. L. Smith, M.S., Associate Agronomist RANGE CATTLE STATION, ONA
Mobile Unit, Chipley W. G. Kirk, Ph.D., Vice-Director in Charge
J. B. White, B.S.A., Associate Agronomist E. M. Hodges, Ph.D., Agronomist
D. W. Jones, M.S., Asst. Soil Technologist
CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Vice-Director in Charge CENTRAL FLORIDA STATION, SANFORD
W. L. Thompson, B.S., Entomologist R. W. Ruprecht Ph.D, Vice-Dir. in Charge
R. F. Suit, Ph .I., Plant Pathologist J. W. Wilson, Sc.D., Entomologist
E. P. Du oarme, Ph.D., Asso. Plant Path. P. J. Westgate, Ph.D., Asso. Hort.
C. R. Stearns, Jr., B.S.A. Asso. Chemist Ben. F. Whitner, Jr., B.S.A., Asst. Hort.
I. W. Sites, Ph.D., Hortieulturist
H. O. Sterling, B.S., Asst. Horticulturist Geo. Swank, Jr., Ph.D., Asst. Plant Path.
H. J. Reitz, Ph.D., Horticulturist
Francine Fisher, M.S., Asst. Plant Path. WEST FLORIDA STATION, JAY
I. W. Wander, Ph.D., Soils Chemist
J. W. Kesterson, M.S., Asso. Chemist C. E. Hutton, Ph.D., Vice-Director in Charge
R. Hendriekson, B.S., Asst. Chemist H. W. Lundy, B.S.A., Associate Agronomist
Ivan Stewart, Ph.D., Asst. Biochemist W. R. Langford, Ph.D., Asst. Agronomist
D. S. Prosser, Jr., B.S., Asst. Horticulturist
R. W. Olsen, B.S., Biochemist
F. W. Wenzel, Jr., Ph.D., Chemist SUWANNEE VALLEY STATION,
Alvin H. Rouse, M.S., Asso. Chemist LIVE OAK
H. W. Ford, Ph.D., Asst. Horticulturist
L. C. Knorr, Ph.D., Asso. Histologist4 G. E. Ritchey, M.S., Agronomist in Charge
R. M. Pratt, Ph.D., Asso. Ent.-Pathologist
J. W. Davis, B.S.A., Asst. in Ent.-Path.
W. A. Simanton, Ph.D., Entomologist GULF COAST STATION, BRADENTON
E. J. Deszyck Ph Ass Horticulturist E. L. Spencer, Ph.D., Soils Chemist in Charge
C. Leonar, Ph.D. Asso. Horticulturist E. G. Kelsheimer, Ph.D., Entomologist
W. T. Long, M.S., Asst. Horticulturist David G. A. Kelbert, Asso. Horticulturist
M. H. Muma, Ph.D., Asso. Entomologist Robert 0. Magie, Ph.D., Plant Pathologist
F. J. Reynolds, Ph.D., Asso. Hort. J. M. Walter, Ph.D., Plant Pathologist
W. F. Spencer, Ph.D., Asst. Chem. Donald S. Burgis, M.S.A., Asst. Hort.
I. EL Holtsberg, B.S.A., Asst. Ento.-Path. C. M. Geraldson, Ph.D., Asst. Horticulturist
K. G. Townsend, BS.A., Asst. Ento.-Path. Amegda Jack, M.S., Asst. Soils Chemist
J. B. Weeks, B.SA., Asst. Entomologist Gerald Eugene Wilcox, Ph.D., Asst. Hort.
R. B. Johnson, M.S., Asst. Entomologist
W. F. Newhall, Ph.D., Asst. Biochem.
W. F. Grierson-Jackson, Ph.D., Asst. Chem. E D LAB AT
Roger Patrick, Ph.D., Bacteriologist FIELD LABORATORIES
Marion F. Oberbacher, Ph.D., Asst. Plant
Physiologist Watermelon, Grape, Pasture-Leesburg
Evert J. Elvin, B.S., Asst. Horticulturist C. C. Helms, Jr., B.S., Asst. Agronomist
EVERGLADES STATION, BELLE GLADE L H. Stover, Assistant in Horticulture
W. T. Forsee, Jr., Ph.D., Chemist Acting in Strawberry-Plant City
on, Ph.D., Fiber Tehnologist A. N. Brooks, Ph.D., Plant Pathologist
R. V. Allison, Ph.D., Fiber Technologist
Thomas Bregger, Ph.D., Physiologist
J. W. Randolph, M.S., Agricultural Engr. Vegetables--Hastings
R. W. Kidder, M.S., Asso. Animal Hush. A. H. Eddins, Ph.D., Plant Path. in Charge
C. C. Seale, Associate Agronomist E. N. McCubbin, Ph.D., Horticulturist
N. C. Hayslip, B.S.A., Asso. Entomologist T. M. Dobrovsky, Ph.D., Asst. Entomologist
E. A. Wolf, M.S., Asst. Horticulturist
W. H. Thames, M.S., Asst. Entomologist Pecan.-Monticello
W. N. Stoner, Ph.D., Asst. Plant Path.
W. G. Genung, B.S.A., Asst. Entomologist A. M. Phillips, B.S., Asso. Entomologist2
Frank V. Stevenson, M.S., Asso. Plant Path. John R. Large, M.S., Asso. Plant Path.
Robert J. Allen, Ph.D., Asst. Agronomist -
V. E. Green, Ph.D., Asst. Agronomist Frost Forecasting-Lakeland
J. F. Darby, Ph.D., At. lant Path. Warren O. Johnson, B.S., Meteorologist
H. L. Chapman, Jr., M.S.A., Asst. An. Hush.
Thos. G. Bowery, Ph.D., Aest. Entomologist
V. L. Guzman, Ph.D., Asst. Hort. Head of Department
M. R. Bedsole, M.S.A., Asst. Chem. In cooperation with U. S.
J. C. Stephens, B.S., Drainage Engineer'
A. E. Kretschmer, Jr., Ph.D., Asst. Soils Cooperative, other divisions, U. of F.
Chem. 4 On leave
INTRODUCTION ....---...--...--- ---- ..........--- ...-...- .-- -................... 5
CONDITIONS UNDER WHICH POISONOUS PLANTS ARE EATEN ........--......... 6
DESCRIPTIONS OF POISONOUS PLANTS -... ................--- .....-- ....-- ....- 7
Tung-oil tree --..........-.......-...................................------------ 7
Prickly poppy ......----------............................ ........................... 10
Boxwood ........ ...- .....- ....----....-...-..------------.... ........- ............. 12
Showy crotalaria -----.....- ..... ...........-... --- 12
Jimsonweed .--------------- ......---.-....-....--..--....---------....--- .. 16
Purple rattlebox .-----.......... ............ ------.......--........--.........- 18
Carolina-jessamine ........-....--.... .------------------................ ....... ----19
Bagpod, Coffeebean ...................................................................... 22
Bitterweed ............... ...... -.......---........ ......--- .............. 25
Hydrangea .....-------....----..... ....--..----.----------------......... 25
Common lantana ---.........--..---- ...-- ...--..... -..- ..-- ...-- ..... 26
Chinaberry ....................................................-.......----............. 30
Common oleander ...-.. --..........- ......... ............. .......................- 32
Pokeweed ...... .......- -----------------.................... -.................... 34
\Eistern bracken ........--------.................... .. .... .................... 335
O aks ................ ...... ....... ........................................... ................ 38
Castor-bean .--. ....-...................................-- -----................. 39
E lderberry ..... .................................................................. ........ ............... 41
vlraceful nightshade ......---- ---............------... ...--------..........--... 42
Sorghum and related plants ..................... .. ... ....................... 44
Carolina laurel-cherry ..................................... .................................... 48
Black cherry ------.........- .. .... ......... ......................- .... ........... 48
Johnson grass .---..............--... ............. ................................- -......... 50
Oriental cocklebur ................... ....-------------- ...... .. .................. 50
Atam asco-lily, Rain-lily .............. ....... ............................. .................... 53
OTHER POISONOUS PLANTS ..--............. ..........---...........------.......... 55
PLANT CAUSING MECHANICAL INJURY .................................................... 56
Poisonous Plants in Florida
ERDMAN WEST and M. W. EMMEL
Poisonous plants have been known to man since before the
time of Christ. A number of references in the Bible allude to the
poisonous properties of some plants. In early times, knowledge
of these plants was used largely for ulterior motive, particularly,
before much was known about metallic poisons. As civilization
progressed knowledge of the poisonous plants has increased, due
largely to the importance of grazing plants in the economy of
In the United States annual losses among livestock caused by
the consumption of poisonous plants has been estimated at many
millions of dollars. It is very difficult to estimate the actual loss
in Florida caused by livestock eating poisonous plants. Losses
have occurred in all parts of the state and in certain instances
have been very severe. The rapid development of the livestock
industry in this state during the past 15 years has placed in-
creased emphasis on the importance of poisonous plants. Losses
from this cause often can be largely prevented, and it is with this
thought in mind that this bulletin is being published.
It is important to realize in dealing with these plants that
publications from other states, while basically correct in the in-
formation contained, do not necessarily reflect conditions here.
Many poisonous plants which are of importance in other states
may be of little consequence in Florida; conversely, some im-
portant poisonous plants in this state are not of particular
significance in other states. Also common names of plants often
differ in many states and even localities. The name "coffee bean,"
for instance, is a common name for at least eight plants in va-
rious Southeastern states. Therefore, it is essential that as much
information as possible be at hand regarding these plants in our
Early diagnosis is an important phase in controlling losses
caused by poisonous plants. In cases of suspected plant poison-
ing in livestock a graduate veterinarian, who by training and
experience should be able to give valuable assistance, should be
consulted as early as possible. In this way what might develop
into extensive losses often can be reduced to a minimum.
6 Florida Agricultural Experiment Stations
Conditions Under Which Poisonous Plants Are Eaten
Most animals will not eat poisonous plants under normal cir-
cumstances. The following conditions are associated with plant
poisoning in this state.
Starvation.-Well-fed animals receiving a properly balanced
ration seldom voluntarily eat poisonous plants. Plant poisoning
is frequent in range animals grazing on scant range during the
winter months. Under this condition there is a shortage of suit-
able grazing and animals eat undesirable plants in an effort to
survive. Whenever possible winter grazing crops should be
planted to supply feedstuff to supplement pasture during periods
Deficient Rations.-Animals receiving a deficient ration,
either improperly balanced or actually deficient in certain re-
quired ingredients, such as often occurs on range, often develop
a craving for something they are not getting and will eat un-
desirable plants in an effort to find it. Thus, it is important that
animals receive adequate amounts of proper mineral supplement
in areas where known deficiencies occur.
Overgrazing and Drouth.-Under conditions in which pastures
are overgrazed, either through grazing too many animals on a
given area and thereby creating a shortage of suitable feed or
through grazing them on pastures made short by drouth or other
conditions, plant poisoning frequently occurs. Under these cir-
cumstances animals attempt to obtain sufficient food and eat
plants they otherwise would not eat. Cyanogenetic plants, par-
ticularly, are potentially dangerous under these circumstances.
Waste and Trash.-Livestock should not be given access to
waste or trash piles, particularly those containing discarded
poisonous plants. For instance, under normal conditions cattle
grazing in tung groves will not eat the foliage of the standing
tree or the fallen nuts. However, if tung branches and nuts are
discarded in a trash pile cattle have been known to consume them
with relish. Oleander and wild cherry are other poisonous plants
usually not eaten in the standing, living condition but readily
eaten when trimmings are discarded in a trash pile.
Newly Plowed Areas.-Such areas should be grazed with cau-
tion. Plowing may expose roots which are poisonous. Dormant
seeds of poisonous plants, such as cocklebur and crotalaria, often
sprout and grow in newly plowed areas, regardless of the season
of the year.
Poisonous Plants in Florida 7
Dry or Partially Dry Water Holes.-During seasons of drouth
dry water holes should be used with caution. The roots of many
water plants are poisonous. When water holes become dry such
roots often are exposed. Partially dry water holes should be
avoided for the reason that stagnant water often contains vari-
ous types of infectious materials and toxic products from disin-
tegrating plant materials.
Incidental and Curiosity.-Occasionally animals consume poi-
sonous plant materials incidentally. For instance, hay may con-
tain a goodly quantity of bracken or crotalaria. Animals eating
the hay are incidentally poisoned by the bracken or crotalaria.
Hogs grazing on peanuts incidentally consume crotalaria seeds
which have fallen to the ground. Many animals have a certain
amount of curiosity. They may eat the hydrangea bush at the
corner of the house when plenty of desirable food is at hand. Or,
they may "eat through the fence" where pastures are always
greener on the other side.
Unknown.-Occasionally it is impossible to determine why
some animals eat poisonous plants. Animals have been known to
graze on poisonous species of crotalaria even though sufficient
quantities of other forage were available. Many theories have
been advanced but none have been definitely proven.
Under normal conditions plant poisoning by certain specific
plants usually is seasonal. Examples are cocklebur and atamasco
lily. However, instances of poisoning by these plants have been
observed where areas infested with them have been plowed or
otherwise disturbed. All poisonous plants are potentially danger-
ous at all seasons of the year and should be so regarded.
Toxicity of seeds, foliage and roots of poisonous plants often
varies from year to year. This is apparently due to variations
in the seasons during which the plants grow. Concentration of
toxins in plants may vary widely from one seedling to another,
or between strains of a given species.
Description of Poisonous Plants
Tung-Oil Tree, Tung Tree, Tung-Nut
Description.-The tung-oil tree (Aleurites fordi Hemsl.1) is a
small-deciduous tree with smooth bark, milky sap, thick twigs
1 The foliage of Aleurites montana (Lour.) Wils., A. moluccana Willd.,
and A. trisperma Blanco grown experimentally in this country is less toxic
than A. fordi in the order named.
8 Florida Agricultural Experiment Stations
and horizontal branches often produced in whorls. The leaves are
alternate, long-stalked and simple. The leaf-blades, 5 to 10 inches
long, are broadly ovate, sharp-pointed, and often exhibit an addi-
tional point on each side of the tip; margins are entire and bases
broad, sometimes rounded. The leaf-stalk bears two reddish or
brownish glands or small knobs close to the leaf-blade. The
flowers are produced in large clusters at the tips of the twigs in
spring before the leaves appear. They are about 1 inch in diam-
eter, consist of 5 to 7 petals colored pale pink or white,
with deep brownish red lines running lengthwise, and have
reddish brown bases. The flowers are of two kinds, several pis-
tillate (female) flowers and many staminate (male) flowers oc-
curring in the same cluster. The fruits, produced on drooping
Fi. 2.-Tun oil leaf, flowers and fruit.
Fig. 2.--Tung oil leaf, flowers and fruit.
Poisonous Plants in Florida 9
stalks several inches long are nearly globular, 2 to 3 inches
in diameter and dark green, later brown, in color. Each fruit
contains three to seven large, hard, rough-coated seeds with
white flesh. (Fig. 2.)
Habitat and Distribution.-The tung-oil-tree, native of China,
has been planted extensively in northern and western Florida as
a source of oil. Stray seeds have produced trees along fencerows,
on roadsides, and in other locations near tung orchards.
Toxicity.-The foliage, sap and fruit, as well as commercial
tung meal, contain a toxic principle, a saponin, which characteris-
tically induces gastro-enteritis in animals to which they are fed.
Commercial tung meal does not contain as much saponin as the
unprocessed fruit; however, it also contains a second toxic sub-
stance as yet unidentified.
Cases of tung poisoning have been reported in cattle, horses
and chickens. One and three-quarters pounds of foliage will kill
a 500-pound steer. Under the common practice of grazing cattle
in tung orchards, cases of poisoning have never been reported.
All known instances of poisonings from foliage have resulted
from animals having access to discarded broken branches or
Symptoms.-Symptoms of tung poisoning in cattle are not
observed until three to seven days after the foliage has been con-
sumed. Acute poisoning results in death in three to four days,
while chronic cases may linger for 18 to 21 days before death
ensues. Hemorrhagic diarrhea which becomes watery and pro-
fuse is a prominent symptom. Lack of appetite, cessation of
rumination, listlessness, depression and unthriftiness are com-
mon symptoms. Chronic cases may develop labored breathing,
mucous discharge from the nose, salivation, cracking of the
skin of the muzzle and progressive emaciation.
Cases of tung poisoning may occur in the human, particularly
from eating the nuts. A severe gastro-enteritis develops with
resultant mild to violent purging. Such cases should be treated
symptomatically under the direction of a physician.
Prevention.-Animals should not be allowed access to dis-
carded branches of the tung tree. Commercial tung meal, unless
detoxified, cannot be used as a livestock food.
Treatment.-Attempts to treat acute forms of tung poisoning
in cattle are useless. Chronic cases can be treated by the ad-
ministration of emollients and drugs to relieve the inflammation
10 Florida Agricultural Experiment Stations
in the gastro-intestinal tract. Tempting soft feeds can be used
to stimulate the appetite.
Description-Prickly poppies, (Argemone mexicana L. and
A. alba Lestib.), (Fig. 3) are upright plants 1 to 3 feet tall bear-
ing several branches near the top. The leaves are 3 to 6 inches
long, armed along the margins with large, very sharp spines.
Fig. 3.-Flowering branch and fruits of prickly poppy.
Poisonous Plants in Florida 11
The sap is thick and white or yellow in color. The flowers,
appearing in late spring and summer, are large, 2 to 4 inches
across, white or clear yellow in color with a cluster of yellow
stamens in the center. The pods are oval, about 1 inch high,
and bear numerous upright spines.
Habitat and Distribution.-Prickly poppies occur as single
plants or in large or small groups anywhere in Florida so long
as the soil is dry. They are frequently found around abandoned
homesites or adjacent fields.
Toxicity.-The plant has been reported to contain several toxic
Fig. 4.-Boxwood-leafy branch.
12 Florida Agricultural Experiment Stations
substances. While cases of livestock poisoning have occurred,
such instances are rare. Mechanical injury sometimes occurs
from the prickly fruit.
Description.-Boxwood, (Buxus sempervirens L. and B. micro-
phylla Sieb. & Zucc.), (Fig. 4) are large or small bushes seldom
over 5 feet in height. The shrubs have many upright branches
and twigs thickly clothed with pairs of round or oval, thick,
leathery leaves about 1/2 inch long. The small dark green leaves
are very persistent and remain on the plant for several years,
but the inconspicuous flowers seldom appear in Florida.
Habitat and Distribution.-Boxwood plants are seldom found
anywhere but in the garden or around the house. They may be
placed singly as specimen plants but more often they are used as
a hedge. They are not found much farther south than Marion
County. Clippings or hedge-trimmings are often dumped into
the pasture lot.
Toxicity.-The bark and leaves contain a number of toxic
alkaloids. Cases of poisoning have been reported in horses and
pigs. All parts of the plant are considered poisonous. Their
bitter taste probably prevents animals from eating large
Symptoms.-Small amounts of the plant have an emetic and
purgative action; large amounts induce intense abdominal pain,
diarrhea, tenesmus, convulsions and death. Extreme thirst, un-
steady gait, convulsions and death have been observed in pigs
which died within 24 hours after eating the plant.
Showy Crotalaria, Yellow Crotalaria
Description.-Showy crotalaria (Crotalaria spectabilis Roth.)
is a robust annual plant 3 to 6 feet or more tall, with an erect,
somewhat ribbed stem bearing several stout, ascending branches.
The alternate leaves are short-stalked and simple; the leaf blades,
4 to 7 inches long, are dark green above, somewhat paler be-
neath, elliptic to cuneate, blunt but often tipped with a bristle.
The stipules are leaf-like and nearly 1 inch long. The yellow
flowers, about 1 inch across, are pea-shaped and borne in up-
right spikes 8 to 15 inches long at the top of the plant and at
the ends of the branches. The smooth pods, nearly 2 inches
long, are inflated, light green when young, becoming nearly black
V jand pod.
14 Florida Agricultural Experiment Stations
when ripe. The seeds, nearly 1/4 inch long, are black and glossy.
The whole plant is smooth to the touch and waxy so that water
stands in drops on the leaves. (Fig. 5.)
Habitat and Distribution.-Showy crotalaria is planted as a
cover crop to enrich the soil and to reduce the population of
root-knot nematode. It occurs commonly also as a roadside plant,
in fencerows, in abandoned fields, around farm buildings, and
about refuse disposal areas. It is seldom found on very wet soils.
It occurs in nearly all parts of the state but is especially common
in farming communities.
Toxicity.-The alkaloid, monocrotaline has been isolated from
the leaves, stems, roots and seed; the concentration is highest
in the seed. Monocrotaline lowers blood pressure and decreases
the rate and amplitude of the heart beat in experimental animals.
Natural cases of poisoning have been observed in cattle,
sheep, goats, horses, hogs, mules, chickens and turkeys. Nine
pounds of the dried plant will kill a 300-pound steer in approxi-
mately four days. Two grams of ground seed fed daily will pro-
duce acute poisoning in 50-pound hogs in about seven days.
Chickens have been killed in 30 to 60 days by consuming 80
The frosted green or dry plant is toxic to all classes of live-
stock if eaten in sufficient quantity.
Wild birds such as quail and turkeys apparently refrain from
Symptoms.-Acute poisoning in cattle is marked by depres-
sion, loss of appetite, bloody feces, drooling saliva, nasal dis-
charge and a yellowish discoloration of the visible mucous
membranes. Death occurs within 5 to 10 days.
The most common type of poisoning observed in cattle under
field conditions is the chronic form in which animals often die
two to six months after eating the plant. In such cases very
little evidence of illness is observed until 7 to 14 days before
death. The hair coat may appear rough and there may be a
slight unthriftiness. Usually the first marked symptom noted
is bloody feces. The eyes have an anxious or staring appearance.
The animal appears slightly bloated and full in the middle. Loss
of appetite, diarrhea, yellowish discoloration of the visible mu-
cous membranes, partial version of the rectum and general
weakness are other symptoms. Before death the animal "goes
down," due to general weakness, and is unable to stand on its feet.
Poisonous Plants in Florida 15
The symptoms of crotalaria poisoning in sheep and goats are
similar to those observed in cattle. The period of illness, how-
ever, is somewhat shorter.
Hogs often die suddenly of gastric hemorrhage in acute cases
of poisoning. Chronic cases may develop two to four months
after the animals have had access to the plant. Loss of appetite,
general unthriftiness, weakness and occasionally anemia occur.
Hogs on feed fail to gain weight.
Horses and mules have been known to become affected with
crotalaria poisoning as long as nine months after contact with
the plant. The first period of illness usually is marked by a
gastro-intestinal disturbance (colic). Usually there is a diarrhea
and congestion and yellowish discoloration of the visible mucous
membranes. Intestinal movements can be heard at a distance of
15 to 20 feet from the animal. Symptoms of extreme stupor and
depression for a period of two or three days are interspersed with
periods of two to six weeks during which the animal appears im-
proved. During periods of severe illness affected animals walk
listlessly, in circles, and stumble into various objects; they also
push or lean against stationary objects and often meet sudden
death by falling into awkward positions or becoming entangled in
fences so that they cannot extricate themselves. The usual
period of illness is three to four months, although some animals
live much longer. During this period the general condition of
the animal deteriorates and emaciation occurs. Death occurs as
the result of cardiac failure.
Chickens and turkeys, particularly poults, often are poisoned
by eating the seed or green plant. Affected birds become listless
and droopy; often there is diarrhea, darkness or paleness of the
comb. Anemia and emaciation usually occur if the period of ill-
ness is longer than two weeks.
Prevention.-Although poisoning by crotalaria may occur at
any time during the year, it is most frequent when this plant
is green and succulent while other forage is dry and unattractive.
It should be considered extremely hazardous to permit livestock
of any kind to come in contact with this plant. There is some
controversy among laymen as to the toxicity of C. spectabilis,
as animals have been known to eat it without inducing illness.
Animals having continual contact with the plant sometimes eat
small quantities throughout the season and in this way develop
a tolerance to the toxic principle. Some animals will not eat
16 Florida Agricultural Experiment Stations
the plant, others will eat it only when insufficient desirable
forage is available, while others may eat it even though they are
well fed. The development of poisoning is dependent entirely
upon the amount the animal eats.
Once the plant has been allowed to scatter its seed on the
ground, many years are required to exterminate it, as some seed
lie in the soil for years before sprouting. Planting inflted
areas in cultivated crops greatly assists in elimination of the
Treatment.-Animals which have developed symptoms of
crotalaria poisoning rarely recover, regardless of treatment.
Jimsonweed, Jimsonweed datura, Jamestown weed, Thorn apple
Description.-Jimsonweed (Datura stramonium L.) is a large
annual weed, three to five feet tall, with several widespreading
branches near the top of the stem. The main stem and branches
are smooth and green or purplish. The alternate leaves are
smooth, light green and stalked; the leaf-blades, 3 to 8 inches
long, are thin, ovate to elliptic, pointed at both ends, and bear
large, irregular, sharp-pointed teeth along the margins. The
erect flowers, borne singly in the leaf axils, are short-stalked,
funnel-shaped but flaring out into a five-pointed star and white
or pale bluish-purple in color. The four-celled fruit is a dry, hard
capsule, ovate, green, becoming pale, brown, and covered with
hard, sharp prickles. The pod, about 1 inch long, splits into four
sections, each containing numerous seeds. (Fig. 6.)
Habitat and Distribution.-Jimsonweed is found nearly all
over the state, but more commonly in the northern areas. It oc-
curs in cultivated fields, gardens, around farm buildings, par-
ticularly old barn lots, roadsides and refuse heaps, nearly always
on fertile soil.
Toxicity.--Jimsonweed contains the toxic alkaloids, hyoscya-
mine, atropine, and scopolamine, about 0.3 percent of the dry
weight of the plant. All parts of the plant, particularly the seeds,
are poisonous. Cattle are poisoned most frequently, but occa-
sionally sheep, horses and hogs are affected. Children have been
poisoned by eating the fruit or sucking the flowers. Ten to 14
ounces of the green plant will produce fatalities in cattle. The
toxicity of the plant is not destroyed by drying and poisoning oc-
casionally has resulted from eating the weed mixed with hay.
Poisonous Plants in Florida 17
Fig. 6.-Jimsonweed-flowering shoot with young fruit.
Cases of poisoning due to ensilage containing the weed have
Symptoms.-Dryness of mouth, rapid pulse and respiration,
partial blindness and frequent urination or retention of urine are
common symptoms in cattle. Diarrhea, dilation of the pupils of
the eyes and stiffness also have been observed. In the terminal
stages of illness respiration becomes slow, weak and irregular,
while the pulse becomes rapid and feeble, with death resulting
Convulsive twitching of the entire body is described as an out-
standing symptom in hogs.
Prevention.-The weed has a rank, unpleasant odor and a
strong taste, and animals are not likely to eat it unless confined
to areas where there is little else to eat.
18 Florida Agricultural Experiment Stations
The plants should be cut and burned before the seeds mature.
Grubbing is considered practical when small areas are involved.
Care should be used that the weed is not included in hay.
Purple Rattlebox, Daubentonia, False Poinciana
Description.-Rattlebox (Daubentonia punicea (Cav.) DC.)
is a shrub or small tree seldom more than 10 feet in height.
The trunk is slender, stiff and usually crooked, bare below and
dividing into several stiff, widely spreading branches at the top.
The bark on the twigs and trunks is dark gray to black and only
slightly roughened with raised lenticels. The alternate leaves,
four to eight inches long, are stalked and pinnate, with 6 to 20
pairs of leaflets. Each leaflet is one inch or less long, elliptic
with a minute, pointed tip, dark green above, smooth and rather
firm. The flowers, borne in pendant clusters near the tips of the
branches, are sweet-pea shaped, orange to red in color, and nearly
1 inch across, on short, slender stalks. The pods, 2 to 3 inches
long and 1/2 inch wide, are green, turning dark brown on ripen-
ing, slightly flattened, pointed at both ends, and furnished with
four flanges or wings running lengthwise the pod. The seeds
are oblong to subglobose and brown. (Fig. 7.)
Habitat and Distribution.-Rattlebox, a native of Mexico, was
originally planted in Florida as an ornamental, but has become
naturalized in many areas of the northern part of the state. It
is most often found around houses, along fencerows and ditch
banks, and in the flood plains of streams.
Toxicity.-The toxic principle is a saponin, the greatest con-
centration being in the seed.
Cases of poisoning have been reported in sheep, chickens and
pigeons. Approximately 50 grams of the plant per hundred-
weight are sufficient to induce fatal poisoning in sheep. Chickens
may be killed by consuming as few as 6 to 18 seeds, while three
or four seeds have been observed to cause death in pigeons.
Symptoms.-The pulse is rapid and respirations are weak,
irregular and usually labored in poisoned sheep. Death occurs
with little or no struggling. Sheep which recover show diarrhea
and depression for several days.
Drooping wings, ruffled feathers, profound depression, gen-
eral debility, unthriftiness, congested comb and profuse diarrhea
are symptoms usually observed in affected chickens.
The period of illness in pigeons is short. The droppings are
Poisonous Plants in Florida 19
Fig. 7.-Rattlebox-flowering shoot and pod.
scant, watery and greenish. General weakness occurs. Recovery
seldom is observed.
Prevention.-Animals should not be allowed to contact areas
in which the plant grows wild, particularly when there is a
shortage of feed. When the plant is grown as an ornamental
the pods should be picked before the seeds have an opportunity
to shatter on the ground.
Treatment.-A saline purgative, followed by stimulants and
soft food, is beneficial.
Carolina-jessamine, Yellow-jessamine, Evening Trumpet-flower
Description.-Carolina-jessamine (Gelsemium sempervirens
(L.) Ait. f.) is a high-climbing, woody vine that often covers the
tops of small trees and bushes but, in the absence of support,
20 Florida Agricultural Experiment Stations
may trail on the ground and produce many slender, more or less
upright stems. The main stems of large vines are gray and one
inch or more in diameter, but the majority of the branches are
thin, wiry, much branched and tangled, glossy and dark reddish-
brown in color. The short-stalked leaves are simple and always
produced in pairs; the leaf-blades, 1/2 to 21/2 inches long, are ovate
to lanceolate, not very sharp-pointed, rounded at the base, smooth
on the margin and dark green, though often marked with ir-
regular reddish-brown discolorations, especially in winter. The
clear yellow, sweet-scented flowers, produced in late winter and
Fig. 8.-Carolina jessamine-flowering stems with fruits.
Poisonous Plants in Florida 21
early spring, are borne in small clusters in the leaf axils of the
slender twigs in such profusion as to form conspicuous masses of
color. The individual flowers, tubular with five flaring lobes, are
1 to 11/, inches long. The seed pods are brown, flat, less than 1
inch long and contain several small, winged seeds. (Fig. 8.)
Habitat and Distribution.-Carolina-jessamine grows abun-
dantly in open hammocks, but is also found in thickets, swamps
and open fields, along fencerows, around stumps, and on rocky
bluffs. The vine is most widely distributed in northern Florida,
but occurs as far south as Osceola County.
Toxicity.-Yellow-jessamine contains the crystalline alkaloid
gelsemine and the amorphous alkaloids gelseminine and gelse-
moidine. Other alkaloids have been reported isolated from the
plant. These alkaloids constitute the poisonous principles in the
plant. They chiefly depress and paralyze motor nerve endings.
Depression of the motor neurons of the brain and spinal cord re-
sult in respiratory arrest.
The flowers, leaves and roots contain the toxic alkaloids, the
greatest concentration being in the roots from which extractions
have been made for medicinal purposes.
Cattle, sheep, goats, swine and horses have been reported
poisoned by yellow jessamine. Poisoning of cattle by this plant
is of considerable importance in the Southeastern states, partic-
ularly during the winter months when there is a shortage of
desirable green feed.
Single dosages of five pounds of green leaves to a 400-pound
steer did not produce typical poisoning attributed to yellow-jessa-
mine as observed in the field. The feeding of 180 grams of fresh
green leaves to hens over a period of 15 days resulted in death in
20 to 26 days, with no indications of symptoms until four or five
days before death. This would indicate that the poisonous prin-
ciple is cumulative and that animals must eat the plant over a
period of time before poisonous effects are observed.
Symptoms.-Under range conditions animals poisoned by this
plant usually are not found until they are "down." Early symp-
toms consist of muscular weakness, staggering gait and dila-
tion of the pupils of the eyes. As weakness progresses rapidly
the animal "goes down" and death usually occurs in 24 to 48
hours. During this terminal period convulsive movements of the
head and legs occur frequently. The pulse is feeble, respirations
are reduced and the temperature usually is subnormal. Animals
22 Florida Agricultural Experiment Stations
in this condition should not be drenched, as paralysis of the
throat often occurs, resulting in an inability to swallow. Death
occurs from respiratory failure.
Prevention.-Animals should not be allowed to graze in areas
where pasture is scant and yellow-jessamine is plentiful. Grub-
bing is a means of eliminating isolated plants. When larger
areas are involved, fencing off or bulldozing can be an effective
Bagpod, Bladderpod, Coffeeweed, Coffeebean
Description.-Bagpod (Glottidium vesicarium (Jacq.) Har-
per) is a robust annual weed, often 6 feet and sometimes 12 feet
high in rich soil. The stems are straight, erect, slender for their
height and branched above the middle with several stiff, wide-
spreading branches, the number depending upon the amount of
competition with other plants. The alternate leaves are widely
spaced on the stem, 4 to 10 inches long, pinnate with 10 to 26
pairs of leaflets. Each leaflet is elliptic with a small pointed top,
1/ to 1 inch long, about 1/ inch wide, dark green above and paler
beneath, very smooth and waxy. The flowers, borne in clusters
of two to five or more on slender stalks 3 to 5 inches long, are
sweet-pea shaped, about 1/2 inch across and yellow striped with
pink or entirely red all over. The pods, which persist long after
the leaves have fallen, are 2 to 3 inches long, elliptic, pointed at
both ends and bulged over each of the two seeds. At maturity
the outer layer of the pod opens and exposes the thin, silky,
white sack-like inner layer enclosing the seeds. The seeds,
nearly 1/ inch long, are oblong and greenish brown. (Fig. 9.)
Habitat and Distribution.-Bagpod occurs nearly all over
Florida. It is found most commonly in old fields, especially on
rich, damp soil, along ditches and streams, around lakes and
savannahs and sometimes on higher land in abandoned cultivated
Toxicity.-The toxic principle of bagpod is a saponin, which
causes intense inflammation of the gastro-intestinal tract.
Cases of poisoning have been reported in chickens; hogs, goats,
sheep and cattle. Approximately 150 mature seeds constitute
a fatal dose for an adult chicken. The green seeds are consider-
ably more toxic than mature seeds. About five pounds of the
green plant and seeds are required to induce fatal poisoning in
a 250-pound steer.
Poisonous Plants in Florida 23
Symptoms.-In affected chickens the comb becomes dark and
congested. A yellowish diarrhea develops. Emaciation and un-
thriftiness occur when the period of illness is prolonged. Bagpod
seeds are found in the crop and gizzard of poisoned birds.
Symptoms of poisoning in cattle and sheep are similar. Marked
depression and sluggishness are among the early symptoms
when diarrhea occurs. The animal urinates frequently. Res-
pirations are shallow and accelerated. Depression increases and
finally the animal passes into a comatose condition and death
Fig. 9.-Bagpod-pods, leaf and flower.
Prevention.-Chickens most commonly are poisoned by the
seeds which fall from the plant during the winter. The weeds
should be mowed in the late summer or before the seeds mature.
24 Florida Agricultural Experiment Stations
Fig. 10.-Bitterweed plant in flower.
Poisonous Plants in Florida 25
Description.-Bitterweed (Helenium tenuifolium Nutt.) (Fig.
10) is an annual or biennial plant 6 inches to 3 feet tall when in
bloom. The green stems are widely branched above the middle
but usually simple below. The leaves are about 1 inch long,
narrow, strap-like and very numerous on both stems and
branches. The flower heads are about 1 inch across, daisy-like
in shape and both rays and the disk-like centers are bright yel-
low. The flower heads are borne on the tips of the branches,
forming a flat-topped mass of flowers.
Habitat and Distribution.-Bitterweed is a plant of waste
places. Large patches may be found along roadsides in central
Florida and westward across northern Florida to the Alabama
line. Old pastures are frequently densely populated with it. It
does not tolerate shade nor does it occur on swampy soil. It is
distributed on both sand and clay soils, well drained or even dry,
usually associated with grasses of some sort.
Toxicity.-Cases of poisoning have been reported in horses and
mules. All parts of the plant contain a bitter principle. The
milk of cows which have grazed on bitterweed commonly pos-
sesses an intense bitter flavor.
Description.-Wild hydrangea (Hydrangea quercifolia Bartr.)
(Fig. 11) is a shrub or small tree sometimes 15 feet in height.
The stems and twigs are usually reddish brown or tan in color.
The large leaves, 6 inches or more long, dark green above,
grayish and fuzzy underneath, are deeply scalloped or lobed on
the margin so that they resemble oak leaves in outline. The
tiny white flowers are borne in large pyramidal panicles often
a foot long. Their color becomes brownish or purplish with age.
Habitat and Distribution.-Wild hydrangea grows naturally
on steep banks of sinkholes, river bluffs and rocky outcrops from
Leon County westward. It usually grows in considerable shade,
only rarely in full sunlight. However, nurserymen often use it
as an ornamental and as such it may be found far out of its
Related Species.-Another wild hydrangea (Hydrangea
arborescens L.) is less common in Florida. It is distinguished
from the above by oval or elliptic leaves lacking the deep lobes.
26 Florida Agricultural Experiment Stations
Fig. 11.-Wild hydrangea flower cluster with leaves.
The garden hydrangea (Hydrangea macrophylla Ser.) (Fig. 12)
is found only in garden or other landscape plantings.
Toxicity.-Wild hydrangea, as well as many of the ornamental
species of hydrangea, contain a glucoside which yields hydro-
cyanic acid. Naturally occurring cases of poisoning by these
species have been described in the horse and cow.
Symptoms.-The character of symptoms produced would indi-
cate the presence of a toxic substance in addition to hydrocyanic
acid potentialities. Extreme restlessness, abdominal pain and
profuse diarrhea, which becomes hemorrhagic and contains
mucus, occur. Guinea pigs fed experimentally developed a se-
Description.-Lantana (Lantana camarca L.) is a shrub or, in
the northern areas, an herbaceous perennial reaching a height
Poisonous Plants in Florida 27
of 3 to 5 feet. The stems are widely branched, brittle at the
joints, usually bluntly square, green or brown and armed with
weak, sharp spines. The leaves, borne in pairs or whorls of
three, are stalked and aromatic when crushed; the leafblades
Fig. 12.-Garden hydrangea flower cluster with leaves.
28 Florida Agricultural Experiment Stations
are ovate or elliptic, somewhat pointed at both ends, dark green
above and paler below, 1 to 3 inches long and toothed along the
margin. The flowers, creamy white, yellow or pink, changing to
orange or scarlet, are borne in long-stalked clusters about 1
inch across in axils of the leaves. The individual flowers have
four lobes or divisions and are tubular in the lower part. The
fruits, green to blue or black, are nearly 14 inch in diameter and
contain one bony seed. (Fig. 13.)
Habitat and Distribution.-Lantana has been planted widely
as an ornamental and is most common around gardens and old
home sites. It is also found along fencerows, in fields and the
margins of woods. It is found nearly all over the state but is
most common from Orlando southward.
Related Species.-Three other species are common in Florida.
L. aculeata L. grows as high as 8 feet, has strongly spiny stems
and yellow flowers, changing to orange or purple. L. ovatifolia
Britton has unarmed stems about 5 feet or less high and yellow,
unchanging flowers. L. sellowiana Link and Otto has weak, un-
armed stems up to 5 feet in length and purple flowers. These
species probably are equally toxic.
Toxicity.-This plant contains a substance which sensitizes
the skin of cattle and sheep which have eaten it to sunlight,
causing the skin to become hard, swollen, cracked and painful.
This process is called photosensitization. Plants having this
action may be eaten and the animal sensitized but lesions will not
develop unless exposure to sunlight follows. Experiments indi-
cate that the feeding of % to 1 pound of mature dried leaves
will induce poisoning in a 400-pound steer.
Symptoms.-The acute type of poisoning is induced when ani-
mals eat a considerable quantity of the plant. The affected ani-
mal shows symptoms of sluggishness or extreme weakness; the
stools usually are soft and bloody; food is refused; occasionally
partial paralysis of the legs occur; death usually occurs within
three to four days.
Chronic cases of lantana poisoning are induced when smaller
amounts of the plant are eaten. Affected animals usually be-
come constipated, particularly in the early stages of poisoning,
although later the stools may become soft. Areas of skin and
mucous membrane show a yellowish discoloration. Although
white or non-pigmented skin shows the first evidence of disease,
pigmented skin often subsequently becomes involved. The skin
Poisonous Plants in Florida 29
Fig. 13.-Lantana-flowering shoot with fruit.
30 Florida Agricultural Experiment Stations
of the muzzle, ears, neck, shoulders, legs, udder or other part of
the body becomes yellow, swollen, hard, cracked and painful. The
skin often peels, leaving large exposed raw areas. The skin of
the muzzle usually is extensively involved. Areas of inflamma-
tion extend to the adjacent mucous membranes of the mouth and
nasal passages. Skin of the muzzle becomes yellowish to orange
in color; it then becomes dry, hard, painful and finally cracks.
The skin may become detached, leaving large bleeding areas ex-
posed. Bacterial infection may occur in such areas and extend
into surrounding tissue. Ulcers often develop on tongue, gums
and lining of the cheeks. Affected animals refuse food; saliva
drools from the mouth; loss of flesh occurs. Skin and membranes
surrounding the eyes may become affected, as well as the eyeball
Prevention.-Lantana poisoning most frequently occurs as a
result of a lack of desirable forage. The crushed leaves have a
pungent odor and taste and animals will not eat them if sufficient
suitable forage is available. Animals unfamiliar with the plant
occasionally become poisoned when moved to pastures in which
it is growing. In most instances it is probably practical to re-
move the plants by grubbing.
Treatment.-Affected animals should be kept in darkness or
shade, out of contact with sunlight. Soft laxative feeds should
be supplied. Affected skin areas should be treated with mild
antiseptics and healing ointments. The percentage of recoveries
usually is not large, even though many times the symptoms
appear mild. Lesions should be closely observed for screwworm
infestation and treated accordingly.
Chinaberry, China-tree, Pride of India
Description.-Chinaberry (Melia azedarach L.) is a small
tree 20 to 40 feet high. The trunk is 1 to 2 feet in diameter,
large in proportion to the rest of the tree, often divided near the
base into several large branches. The bark is gray to dark gray-
brown, roughened by narrow inter-lacing shallow furrows and
broad flat-topped ridges. The alternate leaves, 1 to 3 feet long,
roughly triangular in shape, are twice divided into numerous
leaflets. The leaflets, 1 to 2 inches long, are broadly lanceolate
or ovate in shape, dark green above and paler beneath, and
sharply toothed or lobed along the margins. The fragrant
flowers are produced on long-stalked, much-branched axillary
Poisonous Plants in Florida 31
clusters soon after the leaves attain full size. Each flower is
about 1 inch across and composed of five or six narrow purplish
petals surrounding a pale column of stamens. The fruit is
smooth, globular, yellow, about 1/2 inch in diameter. The one
large stone, covered by thin pulpy flesh, is strongly ribbed length-
wise and contains five or six seeds in small cavaties.
Habitat and Distribution.-Chinaberry is native to Syria,
Iran and northern India but it has been naturalized almost
throughout Florida. It is also common in hammocks and around
abandoned home-sites. (Fig. 14.)
Melia azedarach L. var. umbraculifera Sarg., the umbrella
chinaberry, is a small tree with dense, much-branched, umbrella-
shaped crown. It is frequently planted as an oranmental in
Fig. 14.-Chinaberry-flowering shoot and cluster of old fruits.
32 Florida Agricultural Experiment Stations
Toxicity.-The toxic principle of chinaberry has not been de-
termined. Poisoning occurs most frequently among hogs from
eating the green and ripe berries. The lethal dose for a 50-pound
pig is approximately 150 grams of berries. The fruit is less toxic
for goats, chickens and ducks. While fruits or berries are most
toxic, flowers, leaves and bark also contain the toxic principle.
Symptoms.-In hogs symptoms occur three to four hours
after the berries have been consumed. Loss of appetite, consti-
pation, blood-stained stools, stiffness, lack of coordination and
general weakness are the chief symptoms. Death often occurs
within 24 hours.
Prevention.-Animals, and particularly hogs, should not have
access to the fruit of the chinaberry tree.
Treatment.-Berries of the chinaberry are almost always
found in the stomach or intestines of animals poisoned by this
plant. There is no specific treatment. Affected animals usually
die within a short time after symptoms are noted; those which
survive this period usually do so without treatment.
Description.-Oleander (Nerium oleander L.) is a woody
shrub or small tree ranging in height from 5 to 25 feet. When
allowed to grow naturally it produces a large number of stems
and forms a dense clump, but occasionally plants are trimmed
to a single large trunk with a much-branched crown. The bark
on young stems is smooth and green, but older branches and
trunks are gray and roughened by many raised lenticels. The
numerous short-stalked leaves are borne in pairs or more often in
whorls of three around the twigs; the leaf-blades, simple, narrow,
evergreen, leathery, pointed at the tip, dull dark green above
with a prominent lighter colored midrib, are 3 to 10 inches long
and smooth on the margin. The leaves usually turn yellow before
falling and the leaf-scars are prominent on twigs and branches.
The flowers, produced in early summer or all year in the warmer
parts of the state, are borne in upright clusters at the ends of
branches on the upper part of the shrub. They vary in color
from white through pink, creamy yellow and rose to deep red.
Normally there are five petals about 1 inch long with a fringed
appendage at the base of each, but many cultivated forms with
double (many petalled) flowers are found in gardens. The pods,
not commonly produced, are long, narrow, cylindrical and paired.
Poisonous Plants in Florida 33
The numerous seeds are furnished with a tuft of brown hairs.
All parts of the plants, but especially the new growth, exude a
gummy, sticky sap when injured. (Fig. 15.)
Fig. 15.-Oleander--flowering shoots.
Habitat and Distribution.-Oleander, an exotic plant, is found
only where it has been planted, but it has been widely used for
hedges, screen plantings and as an ornamental. Since it grows
vigorously it must be pruned often and the clippings frequently
find their way to rubbish piles and dumping grounds.
Toxicity.-Two toxic glucosides with properties similar to
those of the digitalis glucosides have been isolated from oleander.
Cases of poisoning have been reported in all classes of livestock,
as well as in humans. Approximately 15 to 20 grams of the
green leaves are sufficient to induce death in mature cattle and
horses. The dry leaves are almost as toxic as the green ones.
34 Florida Agricultural Experiment Stations
Symptoms.-The symptoms of poisoning in horses, cattle and
sheep are rather similar. Affected animals become weak. The
pulse is rapid. Profuse sweating occurs. Purging usually is
present during the entire period of illness. Abdominal pains
often are severe. The extremities are cold. Blood often appears
in the stool in the terminal stages.
Prevention.-The leaves of oleander are fibrous and tough.
Animals will not eat them unless there is a shortage of desirable
Treatment.-Affected animals can be treated by a veterinarian
according to the symptoms shown, but if a lethal dose has been
consumed treatment is of little avail.
Description.-Pokeweed (Phytolacca americana L.) and South-
ern pokeweed (P. rigida Small) (Fig. 16) is a robust herbaceous
plant growing 6 feet or more in height from thick fleshy roots.
The stems, simple below, are much branched above. The stem
and branches are smooth, colored green or purple. The lower
leaves are a foot or more long, gradually diminishing until the
upper are about 3 inches. All are spear-shaped. The flowers
produced all summer are white,.less than 1/4 inch across, borne
in narrow clusters several inches long. The flattened, purple-
black, juicy berries are 1/s to 1/2 inch in diameter and contain
Habitat and Distribution.-Pokeweed occurs all over Florida.
It is most often found in open hammocks and along their margins
but it is also frequent on neglected cultivated land, along fence-
rows and around dumps or trash piles.
Toxicity.-Pokeweed contains a toxic alkaloid and also a toxic
substance called phytolaccotoxin. All parts of the plant, prin-
cipally the berries and roots, are considered toxic to cattle,
sheep, horses and hogs. Cases have been reported in which
children were poisoned by eating the berries and roots of the
plant. The young leaves have been used as greens after thorough
boiling and discarding the first water.
Symptoms.-Symptoms occur about two hours after the plant
has been consumed. Severe gastric intestinal irritation occurs.
Nausea, vomiting, purging, retching, spasms and severe con-
vulsions occur, with death resulting from paralysis of the res-
Poisonous Plants in Florida 35
Prevention.-The plants are not difficult to eradicate.
Treatment.-The administration of bland oils and gelatinous
foods has been suggested.
Fig. 16.-Branch of Southern pokewood bearing flower and fruit clusters.
Eastern Bracken, Brake, Brake Fern, Hog Brake, Upland Fern
Description.-Bracken (Pteridium latiusculum (Desv.)
Hieron.) is a coarse, herbaceous fern with long, stout, under-
36 Florida Agricultural Experiment Stations
ground rootstocks or stems. The rootstocks, often 10 feet long,
are black or dark brown, 1/2 inch or more in diameter and some-
times branched. The leaves, with stalks 1 to 3 feet long, are
produced singly from the joints of the rootstock so that they
occur in lines or rows; the leaf-blades, 1 to 3 feet across and
roughly triangular in shape, are divided into three main seg-
Fig. 17.-Leaf of bracken.
Poisonous Plants in Florida 37
ments, each of which is twice divided into smaller parts and
finally the leaflets; the leaflets are very numerous, oblong or nar-
rowly triangular, light to dark green in color and turned down
at the edges. Young leaves are coiled at the top of the develop-
ing leaf-stalk. There are no flowers. Spores or reproductive
bodies, borne in a line of tiny sacs (sporangia) along the edge of
the lower side of the leaves, are dust-like and light brown in
color. (Fig. 17.)
Habitat and Distribution.-Bracken occurs in open, sandy
areas, pastures, open woods, rocky fields, and sometimes in open
spaces in hammocks. It is common over most of Florida as far
south as Lake Okeechobee.
Toxicity.-The toxic principle of bracken is unknown. Cases
of poisoning have been observed in cattle, horses and chickens.
Drying does not destroy the toxicity of the plant. Therefore,
hay and bedding contaminated with the fronds are dangerous.
The toxic principle has an accumulative action. One heavy feed-
ing on the fronds will not cause poisoning. Typical bracken
poisoning is caused by animals eating three or four pounds of
the fronds daily; illness develops three or four weeks later.
Symptoms.-Cattle affected with bracken poisoning usually
have a high temperature, stand with head down and drool.
Bloody fluid trickles from the nostrils. Blood appears in the
feces, either as black masses or bright red clots. The pulse
becomes fast and weak, while respiration often is labored. Death
often occurs within 48 hours after the onset of symptoms.
An unsteady gait usually is the first symptom observed in
horses affected with bracken poisoning. They become drowsy,
push the head against solid objects, and often have difficulty in
swallowing. From 7 to 20 days after the onset of symptoms, the
animal "goes down." General weakness increases and death
occurs in several days, even though the animal may regain its
Prevention.-As a general rule animals eat bracken only when
starving, on inferior forage, or on overgrazed pastures. Hay
containing bracken should not be fed. Bracken areas in pastures
should be plowed and reseeded.
Treatment.-Some animals recover if treatment is adminis-
tered early. Saline purgatives- or linseed oil should be given.
Affected animals should be kept in a quiet place. Soft laxative
feeds are beneficial. Recent reports in literature indicate that
38 Florida Agricultural Experiment Stations
repeated doses of thiamine hydrochloride injected intravenously
or intramuscularly are of considerable benefit in alleviating
symptoms of bracken poisoning.
Description.-Florida oaks (Quercus spp.) vary in size from
low shrubs to tall trees and the leaves may be small or large,
evergreen or deciduous, entire or deeply lobed. In spite of their
variety of size, leaf form and character, they have one character
in common, the fruits of all kinds are acorns.
Fig. 18.-Turkey oak twig with leaves and acorn.
Poisonous Plants in Florida 39
Habitat and Distribution.-Oaks are among the most common
of Florida trees, for a total of 28 species or varieties are native
in the various parts of the state. Turkey oak, also known as
Sand Black Jack and Scrub Oak (Quercus laevis Walt.) (Fig.
18) is a well known and widely distributed species especially
common on the rolling sandy ridges known as high pine turkey
oak land or black jack ridges. It is common in the drier parts
of many cattle ranges. Many other kinds such as white, basket,
chestnut, red, scrub, runner, laurel, water, live and swamp oak
are common and readily recognized in various parts of the state.
Toxicity.-The toxic principle of oak leaves is unknown. Their
toxicity is not due to the tannic acid content.
Oak poisoning occurs chiefly in cattle and sheep. Poisoning
occurs as a result of eating buds, green shoots and young leaves
as an almost exclusive diet when other forage is scarce, and
consequently has been observed most frequently during the
winter or spring.
Cases of acorn poisoning have been described in horses.
Symptoms.-Obstinate constipation is an early symptom. The
stool is hard and lumpy and often covered with mucus and blood
after a few days of illness. Constipation occasionally is followed
by diarrhea. The animal is gaunt, the hair coat is rough and
the muzzle is dry and cracked. Inappetence occurs early usually
with increased thirst. Respirations and temperature usually
remain normal but the pulse is weak. There is marked depres-
sion and evidence of abdominal pain. Affected animals become
progressively weaker and die within 2 to 14 days. In extended
illness emaciation occurs.
Prevention.-Animals should not be allowed to feed exclusively
on oak leaves. Other feed should be provided, so that large
quantities of oak leaves will not be consumed.
Treatment.-Treatment of affected animals is not particularly
satisfactory. Saline purgatives followed by emollients are of
some value in treatment.
Castor-bean, Palma Crista, Castor-oil Plant
Description.-Castor-bean (Ricinus communis L.) is a robust
annual herb (or small tree southward). The strong stems, 4
to 10 feet high, are erect, often crooked, green or red to purple
and sometimes covered with a white, waxy coating. The alter-
nate leaves, 4 to 30 inches across, are simple and borne on long,
40 Florida Agricultural Experiment Stations
stiff stalks; the leaf-blades are thin with prominent ribs, green
or reddish, star-shaped with 5 to 9 or more lobes, thin and
finely toothed along the margin. The stalk is attached to the
leaf-blade some distance in from the edge. The flower clusters
are produced at the ends of branches, but because lateral
branches grow past them they appear lateral. The flowers, pro-
duced in narrow, upright clusters 6 to 12 inches long, are green-
ish white or reddish brown, about 1/2 inch across and lack petals.
The fruits are erect, oval, green or red and covered with stiff,
fleshy spines. The seeds, three in each pod, are about 1/2 inch
long, elliptic, black, white or mottled with gray, black, brown
and white. (Fig. 19.)
Habitat and Distribution.-Castor-bean, a native of the tropics,
Fig. 19.-Castor-bean-flowering shoot, leaf, fruits and seed.
Poisonous Plants in Florida 41
has been widely planted as an oranmental and to a less extent
as a crop plant. From these plantings, seeds have been scattered
widely all over Florida. It is common on rich soil in gardens,
around dumping grounds and in the Everglades around Lake
Toxicity.-Castor-bean contains a poisonous principle, ricin,
which is a true protein.
All parts of the plant, particularly the beans, are toxic for all
classes of livestock. Castor pomace contains the toxic principle
and should not be used as feed for livestock.
Symptoms.-The symptoms of poisoning in horses, cattle and
sheep are similar. Nausea, violent purgation which is sometimes
bloody, and general toxic symptoms are observed. In case of
prolonged illness, muscular tremors, general weakness and emaci-
Prevention.-Livestock seldom eat the plant or beans when
sufficient desirable feed is provided.
Treatment.-No specific treatment for castor-bean poisoning
can be recommended.
Description.-Elderberry (Sambucus canadensis L. and S.
simpsoni Rehder), (Fig. 20) is a weak shrub or small tree 20
feet or less tall, often forming thickets of considerable extent.
The leaves are in pairs, each leaf consisting of 5 to 11 leaflets,
with the basal leaflets divided into smaller leaflets in the Florida
species. The flowers are tiny but borne in large flat-topped
clusters on the ends of the branches. The flowers and the purple
fruits that come later are about 1/ inch in diameter. Flowers
and fruits are often found on the bushes at the same time.
Habitat and Distribution.-Elderberries usually grow in full
sunlight on moist soil. They may be found almost anywhere in
the state but are most common in swamps, along streams and
in the Everglades.
Toxicity.-It has been reported that the fresh leaves, flowers,
uncooked berries, and particularly the roots of elderberry con-
tain a glucoside which is capable of producing small amounts of
hydrocyanic acid. Cooking the berries is said to destroy the
cyanogenetic glucoside. The plant has a bitter taste imparted
to it by the presence of an alkaloid.
42 Florida Agricultural Experiment Stations
Fig. 20.-Elderberry-flower cluster with leaves and part of a fruiting
"Graceful Nightshade, Black Nightshade, Deadly Nightshade
Description.-Nightshade (Solanum gracile Link.) is a ten-
der, low-growing plant with spreading or upright green stems
and numerous branches. It may persist through the winter in
protected places or grow all year in southern Florida. The al-
Poisonous Plants in Florida 43
ternate leaves, 1 to 4 inches long, are borne on rather short
leaf-stalks that merge into the leaf-blade. The leaves are oblong,
oval or narrow, pointed at both ends, with wavy or sometimes
slightly toothed margins. The flowers, borne at the leaf-axils in
stalked clusters, are white, star-shaped with 5 petals and a
yellow protruding center. The small berries, about 1/4 inch in
diameter, become purple or black when ripe. Each berry con-
tains several small, flat, yellowish seeds embedded in greenish
pulp. (Fig. 21.)
Fig. 21.-Nightshade-flowering shoot with fruit, flowers and berry.
Habitat and Distribution.-Nightshade grows nearly every-
where except close to salt water. It prefers shady locations but
is found also in open sunny places, often among high weeds, along
44 Florida Agricultural Experiment Stations
fencerows, in old fields and gardens, and especially along the
edges of hammocks.
Toxicity.-The leaves and unripe berries contain a saponin-
like alkaloidal glucoside, solanin. It has a paralytic action on the
motor and respiratory centers of the brain. The greatest concen-
tration of alkaloid is contained in the unripe berries; the ripe
berries often are consumed by birds and humans without harm.
The green plant and unripe berries have been reported poison-
ous to all classes of livestock, including chickens.
The amount of alkaloid in the plant is said to vary with soil,
climatic and growth conditions.
Symptoms.-Weakness, stupor, staggering gait, extreme nerv-
ousness, staring eyes, dilated pupils and paralysis are symptoms
of nightshade poisoning in cattle, sheep and hogs. The progress
of the symptoms usually is rapid and poisoned animals often are
Prevention.-The plant normally is an annual growing from
the seed only, except in the southern counties; it should be re-
moved and destroyed before the berries form. Eradication by
this means is not difficult.
Treatment.-No treatment is known for nightshade poisoning.
Sorghum, Sorgho, Kafir, Dura, Milo, Feterita, Shallu, Kaoliang,
Broomcorn, Sudan Grass
Description.-Sorghum (Sorghum vulgare L.) and its varie-
ties compose a large group of coarse annual grasses, with up-
right stems 2 to 15 feet in height having 7 to 18 joints. There
may be several lateral shoots at the base. The leaves, one at
each joint, are long, narrow, sharply toothed along the margin,
and have a prominent midrib, white, gray or yellow in color.
The flower cluster or seed head varies from 5 to 18 inches in
length (longer in broomcorn) and may be dense or open and have
the branches erect, spreading or drooping, but always in whorls.
The seeds and kernels of the various kinds of sorghum vary in
size, shape, and especially in color, being white, pink, yellow,
buff, brown or reddish brown. (Fig. 22.)
Habitat and Distribution.-Sorghum and its varieties are
seldom found except where they have been planted, although
spilled seeds may occasionally produce plants along lanes and
around farm buildings. They are widely planted in the northern
part of the state for syrup, grain for feeds, hay and ensilage.
cluster with leaf.
46 Florida Agricultural Experiment Stations
Toxicity.-Although sorghum and its varieties are widely
grown as feed crops, they become toxic under the conditions de-
scribed below. They belong to a group known as cyanogenetic
plants. Such plants contain a glucoside from which prussic acid
or hydrocyanic acid is liberated. Hydrocyanic acid is one of the
most potent poisons known. The acid must be liberated from the
glucosidal combination before poisoning can result. Enzymes
which are present in the plant tissues free the hydrocyanic acid
from the remainder of the glucoside. The acid is absorbed and
carried by the blood stream to the body tissues where the action
of the oxidative enzymes is inhibited. The tissues fail to receive
oxygen. The process is one of internal asphyxiation.
A number of factors affect the amount of cyanogenetic glu-
coside found in the plant. The application of nitrogenous fertil-
izers has been known to increase it 20 times, particularly on
poorer soils. The amount of glucoside in the plant decreases as
it matures. Differences in cultural practices and climatic condi-
tions cause variation in glucosidal content. Second growth and
plants stunted by drouth or other unfavorable conditions are par-
Much of the hydrocyanic acid is set free when the cut plant is
dried slowly. Sorghum raised under drouth conditions is par-
tially dry when cut, dries quickly, and therefore is potentially
dangerous and should be fed with caution.
Cyanogenetic plants killed by frost often are dangerous for
a number of days. While this may appear to be true in some in-
stances, probably more important are the conditions under which
the plant is fed, as well as physical conditions in the stomach of
the animal to which it is fed.
Symptoms.-Lethal amounts of hydrocyanic acid cause death
almost instantaneously, with spasms and respiratory paralysis.
Smaller doses cause a short period of initial stimulation, as-
sociated with excitement and convulsions. Depression then oc-
curs. Respirations become deeper and accelerated, later to
become weak and irregular before finally ceasing. The pupils
are dilated. The eyes are prominent, glassy, staring and non-
sensitive to light. The nostrils and mouth usually are filled with
foam. Involuntary urination and defecation often occur.
Prevention.-The feeding of concentrates tends to prevent in
the rumen the liberation of hydrocyanic acid from sorghum
which may be eaten within approximately 24 hours thereafter.
Large amounts of dextrose also tend to reduce harmful results.
Poisonous Plants in Florida 47
Drouth-injured sorghum can be utilized with safety if placed in
"a silo, adding sufficient water to insure fermentation.
Treatment.-Hydrocyanic acid poisoning progresses rapidly if
"a fatal dose has been consumed. Treatment, if beneficial, must
be administered before respiratory paralysis begins to occur.
Sodium nitrite, sodium thiosulphate, or both in combination, as
well as methylene blue with calcium gluconate administered
intravenously are effective antidotes. Treatment should be given
promptly and preferably by a veterinarian.
Fig. 23.-Laurel-cherry-flowering and fruiting shoots.
48 Florida Agricultural Experiment Stations
Carolina Laurel-cherry, Cherry-laurel, Mock Orange
Description.-Laurel-cherry (Prunus caroliniana Ait.) is a
shrub or small tree sometimes reaching a height of 25 feet. The
trunks are nearly black, dull, crooked, and often bear many lat-
eral branches. The alternate leaves are short-stalked and
simple; the leaf-blades, 2 to 4 inches long, are elliptic, pointed
at both ends, very glossy on the upper side, and bear few to many
sharp teeth along the margins. The pinkish white flowers ap-
pear in late winter or early spring in thick racemes 1 to 2 inches
long in the axils of the leaves. The individual flowers, about 1/4
inch in diameter, bear five small round petals. The fruits,
bluish-black to black and nearly 1/ inch in diameter, are borne
in clusters of two to five, often persisting until the flowers of the
following season appear. Each fruit contains one round stone
covered with dry, purplish flesh. The leaves, twigs and kernels
smell strongly of peach-kernel odor when crushed. (Fig. 23.)
Habitat and Distribution.-Laurel-cherry is commonly used
as a hedge plant around homes and to mark driveways. It also
occurs in thickets at the edges of woods and hammocks and along
fencerows. It is found all over the state.
Toxicity.-Cherry-laurel is a cyanogenetic plant. See discus-
sion under sorghum.
Black Cherry, Wild Cherry, Wild Black Cherry, Rum Cherry
Description.-Black cherry (Prunus serotina Ehrh.) is a
medium to large native tree, sometimes becoming 100 feet tall
and 5 feet in diameter, but small specimens are more common.
The bark on the trunk and branches is smooth, glossy, reddish
brown to black and marked with numerous lines running around
the branches. On old trunks the bark becomes dull, black and
broken into blocks or ridges. The alternate leaves are slender-
stalked and simple; the leaf-blades, 2 to 6 inches long, are slightly
leathery when mature, elliptic, pointed at both ends or rounded
at the base, and have numerous small stiff teeth along the
margins. The leaves fall early in autumn, often assuming bright
red or yellow colors at that season. The small white flowers are
produced early in spring on short lateral twigs bearing one to
two small leaves and 20 or more stalked flowers. Each flower,
about 1/2 inch broad, bears five small round white petals. The
fruits are glossy dark purple to black when ripe and each
contains one hard, nearly round stone embedded in juicy, purple
Poisonous Plants in Florida 49
flesh which is edible and has a sweet acid flavor. When leaves,
twigs or kernels are crushed, they emit the odor of peach-
kernels. (Fig. 24.)
Fig. 24.-Wild Cherry-leaf, flowering shoot and fruit cluster.
Habitat and Distribution.-Black cherry is found as scattered
individuals, seldom in pure stand, from Orange County north and
west to the boundaries of the state. Trees are common along
fencerows where birds have distributed the seeds, as well as in
hammocks, open woods and pastures. In some areas the tree is
best known for its medicinal bark and valuable- cabinet wood.
50 Florida Agricultural Experiment Stations
Toxicity.-Black cherry contains the cyanogenetic glucoside,
amygdalin, which, upon being hydrolyzed by enzymes in the
plant, yields hydrocyanic acid. Poisoning frequently occurs
from eating the young shoots or broken or discarded branches.
The leaves, bark and stones of the fruit contain the glucoside.
Young leaves are considered more toxic than mature ones. (See
discussion under sorghum.)
Description.-Johnson grass (Sorghum halepense (L.) Pers.)
is a coarse, weedy perennial grass, 2 to 5 feet tall, with rough
scaly rhizomes or underground stems extending in all directions.
The flowering stems are erect, 1/4 to 1/ inch in diameter, light
green and often marked with dark red or brown diseased spots.
The leaves are long and narrow, usually less than 1 inch wide
and with a prominent, pale midrib. The flower cluster or panicle
is terminal at the top of the stem, 6 to 20 inches long and bears
numerous flowers and seeds. Each flower or spikelet is narrowly
ovate, nearly erect, slightly hairy or silky and furnished with a
hair-like awn about 1 inch long which is bent below the middle
to form a blunt angle. (Fig. 25.)
Habitat and Distribution.-Johnson grass is found in open
ground, cultivated fields, roadsides, around barns and farm yards
and in waste areas around rubbish piles. It occurs nearly all
over the state, but is most common in cultivated areas.
Toxicity.-Johnson grass is a cyanogenetic plant. It contains
a glucoside which yields hydrocyanic acid on hydrolysis. See
discussion under sorghum.
Oriental Cocklebur, Clotbur, Cocklebur
Description.-Cocklebur (Xanthium pungens Wallr.) is a ro-
bust annual weed 1 to 4 feet tall with stout stems and spreading
branches. The leaves are alternate, long-stalked and simple;
the leaf-blades, 2 to 10 inches long, are nearly heart-shaped or
triangular, with toothed and sometimes lobed margins. The
whole plant feels rough to the touch and the stems are often
spotted with small dull red patches. Although the flowers are
greenish and inconspicuous, the fruits are very prominent. These
pods, about 1 inch or less long, are oblong, green or brown, cov-
ered with hooked prickles, and bear two longer, hard spines at
the end. Each bur contains two seeds, one of which germinates
Fig. 25.-Johnson grass
-flower cluster with leaf;
52 Florida Agricultural Experiment Stations
the next season and the other may not grow until several years
later. Each seedling has two thick, fleshy, dark green seed-
leaves about 1 inch long. (Fig. 1.)
Habitat and Distribution.-Cockleburs occur most commonly
in old fields, but also in more recently cultivated soil, especially
in low areas. They also occur along ditches, streams and road-
sides. The weed is most common in the central, northern and
western areas of Florida.
Toxicity.-The germinating seeds and young seedlings con-
tain the highly poisonous glucoside, xanthostrumarin. Young
seedlings are extremely rich in this toxic principle and are dan-
gerous to all classes of livestock. At this stage of growth they
have two long, rather narrow, pointed leaves which appear en-
tirely different from the mature cocklebur leaf. Thus, they often
are not recognized. As the plant develops from this stage it
gradually loses its toxicity. The mature plant has a bitter, dis-
agreeable taste and animals usually will not eat it.
There is some question as to whether the dormant seeds of
cocklebur are poisonous. They are covered with a spiny bur and
animals do not consume them readily. Occasionally, young pigs
have been known to eat the seeds, which sometimes cause choking
and produce an inflammation in the stomach. However, exten-
sive losses in swine never have been attributed to eating cockle-
bur seeds. Considerable loss in the value of graded wool is re-
ported each year as a result of cockleburs becoming entangled in
the wool of sheep. Extensive irritation of the sheath of steers
and bulls occasionally occurs as the result of masses of cockle-
burs becoming embedded in the hair in this area.
Cocklebur poisoning occurs chiefly in the early spring as a re-
sult of animals, particularly hogs, eating young plants in the
cotyledon stage. The plants usually are found on low, wet land
which has recently dried. Under these conditions a large num-
ber of seeds sprout over a short period. These young seedlings
often constitute the only available green material for grazing
at the time. In the early spring hogs usually are hungry for
green vegetation. Cocklebur seedlings are succulent and ap-
parently palatable, as hogs eat them with relish, even though
the animals are well fed otherwise.
One-quarter to 1/2 pound of the seedlings consumed over a
short interval will kill a 30- to 60-pound pig in 6 to 24 hours.
Smaller quantities consumed over a longer period often result
Poisonous Plants in Florida 53
in cases of poisoning, although the animals may live for four to
five days after initial symptoms are shown. The seedlings are
reported to be equally as toxic for sheep as for swine. A dosage
of twice this amount is required to poison calves. A dosage of
20 grams, which represents about 30 seedlings, will kill two-
pound cockerels within 24 hours.
Symptoms.-The initial symptom of cocklebur poisoning in
pigs is depression, often accompanied by nausea and occasionally
vomiting. Affected animals become gaunt, weak and unable to
stand. Respiration is labored. The pulse is rapid and weak.
Affected animals unable to rise often paddle their legs in running
movements until too weak to do so. The progress of symptoms
depends in a large measure upon the amount of seedlings con-
sumed. When injury results from eating the seedlings in
amounts not large enough to produce death, several weeks are re-
quired for the animals to regain their normal condition.
Symptoms of cocklebur poisoning in sheep and cattle are
quite similar to those in hogs. However, vomiting does not oc-
cur, but trembling and quivering of the muscles often are noted.
Prevention.-Cockleburs are difficult to eradicate, as some of
the seeds do not germinate for several years. In some areas it
may be practical to mow the weeds before the seed mature.
Pigs as well as sheep and calves should be confined in fields
which do not harbor cockleburs until the danger from young
seedlings is past.
Treatment.-The administration of milk, oils or fats is con-
sidered to have some beneficial effects in treating cocklebur
poisoning. However, when symptoms occur the major portion of
the toxic principle has been absorbed; the poison also acts
quickly, which reduces the benefits to be derived from treatment.
Efforts should be made to prevent animals from consuming the
Atamasco-lily, Easter-lily, Rain-lily
Description.-Atamasco-lily (Zephyranthes atamasco Herb.)
is a low, herbaceous, perennial bulbous plant, commonly growing
in clumps. The bulb, buried one or two inches deep, is ovoid, one
inch or less in diameter, composed of layers (like an onion),
white inside but covered with a thin brown skin-like coat. The
leaves, which appear late in fall or early spring, are narrow,
grass-like, 4 to 10 inches long and about /4 inch wide, erect or re-
clining, and bluish green in color. The flowers, appearing in
54 Florida Agricultural Experiment Stations
Fi. 26Rain lilytwo entire lantswithflowers leaves and bulbs.
",' i ) S",
Fig. 26.-Rain lily-two entire plants, with flowers, leaves and bulbs.
Poisonous Plants in Florida 55
early spring, are borne erect on upright, slender stalks 2 to 6
inches long, one on each stalk. The flower, 2 to 3 inches long, is
composed of six petal-like parts like a six-pointed star, the points
spreading or curling back, white or pinkish in color and with six
golden yellow stamens on short stalks near the center. The seed-
pods are three-angled, about 1/ inch across and contain several
smooth, flat, black seeds. (Fig. 26.)
Habitat and Distribution.-Atamasco-lily or a close relative
grows nearly all over Florida. It is most common in flatwoods,
low grassy fields and in the northern areas on tussocks in
Related Species.-Z. treatiae S. Wats. has narrow leaves, 1/8
inch wide, and grows scattered in flatwoods. Z. simpsoni
Chapm., growing in the southern areas, has flowers which do not
open wide, the floral parts remaining erect.
Toxicity.-Cases of poisoning have been observed in horses,
cattle and chickens. The bulb is the most poisonous part of the
plant. It has an extremely acrid taste. Approximately two
pounds of the fresh bulbs will prove fatal to a 300- to 400-pound
steer. Forty grams of bulbs is lethal to a mature chicken.
Symptoms.-The feces become soft in cattle and horses and
often streaked with bloody mucus. Staggering occurs within 48
hours after the plant has been consumed. The affected animal
collapses suddenly and usually dies without struggle.
Prevention.-Animals should not be allowed to graze infested
areas in the spring when there is not an abundance of desirable
Treatment.-No treatment can be recommended.
Other Poisonous Plants
Plants named in the following list occur throughout Florida
and are known to be poisonous under some conditions. While it
may be said that the first eight are perhaps more poisonous than
the remainder, results of eating them chiefly depend on amounts
eaten. Almost all will produce symptoms and death if a suf-
ficient quantity is consumed. Those marked are introduced or
foreign plants used in Florida for ornamental or other purposes.
"*Abrus praecatorius L., jequirity rosary pea, crab-eye.
*Crotalara retusa L., crotalaria.
Crotalaria sagittalis L., arrow crotalaria.
56 Florida Agricultural Experiment Stations
*Delphinium spp., hardy larkspurs.
*Jatropha curcas L., barbados nut.
Kalmia latifolia L., mountain laurel kalmia.
*Melilotus officinalis (L.) Lam., yellow sweet clover.
Aesculus pavia L., red buckeye.
*Allamanda cathartic L., common allamanda.
Amianthemum muscaetoxicum (Walt.) A. Gray, crow poison.
Apocynum cannabinum L., hemp dogbane.
Asclepias tuberosa L., butterfly milkweed.
Asclepias verticillata L., whorled milkweed.
Cephalanthus occidentalis L., common buttonbush.
Cicuta curtissii C. & R., curtiss water hemlock.
*Colocasia antiquorum Schott, elephant's ear.
Euphorbia heterophylla L., painted euphorbia, wild poinsettia.
Euphorbia maculata L., spotted euphorbia.
*Gloriosa superba L., glorylily.
Gossypium spp., cotton.
Lachnanthes tinctoria Ellis, blood redroot, paintroot.
Leucothoe catesbaei (Walt.) Gray, drooping leucothoe.
Leucothoe racemosa (L.) Gray, sweetbells leucothoe.
Lobelia cardinalis L., cardinal-flower.
Lupinus perennis L., sundial lupine.
Lyonia mariana (L.) D. Don., staggerbush lyonia.
Lyonia ligustrina (L.) DC., he-huckleberry.
*Nicotiana glauca R. Grah., tree tobacco.
Oxypolis filiformis (Walt.) Britton, leafless cowbane.
*Phaseolus lunatus L., lima bean.
Ranunculus spp., buttercups.
Solanum carolinense L., carolina horse-nettle.
*Solanum tuberosum L., potato.
Tephrosia virginiana (L.) Pers., Virginia tephrosia.
*Thevetia peruviana Schum., luckynut thevetia, yellow oleander.
Triglochin striata R. & P., ridged podgrass, arrow grass.
Plant Causing Mechanical Injury
Hairy indigo (Indigofera hirsuta L.) is not a poisonous plant.
In some instances when cattle graze hairy indigo the skin of the
legs from the hoof as far up as the knees becomes swollen,
scabby, cracked and often bleeding. Whether this. condition is
due to a mechanical injury following continual wetting of the
Poisonous Plants in Florida 57
skin of the legs, as occurs when well grown hairy indigo is
grazed daily, or due to other factors or combination of factors
is not known. In such instances, however, affected animals
should be confined to keep the skin of the legs dry and only al-
lowed on short pasture after it is dry from dew or rain. The
affected areas should be watched closely for screwworm infesta-
tions. Sulfa ointments applied to the areas facilitate healing.
Fig. 27.-Hairy indigo-flowering shoot with fruit cluster.
The authors wish to thank Miss Esther Coogle, Artist and Assistant in
Research, College of Agriculture, for preparing the illustrations used in
this bulletin. All of them were made from living specimens.
The Many Thousands of Specimens in Our
Help Enable Our Botanists to
Identify Plants Quickly
If you suspect that poisonous plants are causing losses
of your animals, see your County Agent, call a Local Vet-
erinarian, or send specimens of the plants to
AGRICULTURAL EXPERIMENT STATION