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A GUIDE AND KEY TO THE

AQUATIC PLANTS OF THE

SOUTHEASTERN UNITED STATES

Reprint of Public Health Bulletin 286 (1944)

Institution

UNITED STATES DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

Bureau of Sport Fisheries and Wildlife

Circular 158

76 3

OEMCO

FEDERAL SECURITY AGENCY
U. S. PUBLIC HEALTH SERVICE

Ho. 2g,c.

Public Health Bulletin No. 286

A GUIDE AND KEY TO THE AQUATIC PLANTS OF
THE SOUTHEASTERN UNITED STATES

so

I CO

By

DON E. EYLES, Associate Biologist

and

J. LYNNE ROBERTSON, Jr., Sanitary Engineer

with original drawings

by

GARNET W. JEX

From the Division of Infectious Diseases
National Institute of Health

D~ Prepared by direction of the Surgeon General

Issued by U. S. Public Health Service, 1944
Reprinted without change by Bureau of Sport Fisheries and Wildlife, 1963

U.S. Government Printing Office, Washington: 19G3

ACKNOWLEDGMENTS

Acknowledgement is due many who have kindly made determinations of ma-
terial of different groups, and especially Mary Stipe Eyles, who impartially tested
the keys both in the field and in the herbarium.

Fifteen figures in the key (No. 8, 11, 12, 15-19, 23, 25-28, 30, and 32 of Group
A) have been borrowed from Coker and Totten, Trees of the Southeastern States.
Sixty drawings (No. 2, 4, 10, 13, 14, 20-22, 24, and 34-36 of Group A; No. 4 and
6 of Group B; No. 18, 21, 23, 28, 32, 33, 35, and 36 of Group D; No. 11, 12, 14,
17, and 25-28 of Group E; No. 1, 2, 10, 21, 22, 27, 28, 33, 38, 39, 45, 46, 49, 54,
55, 57, 63, 64, 66, 68, 70, and 71 of Group F; No. 1-4 of the Alismaceae; No. 8 of
the Gramineae; and No. 4, 6, 9, and 13 of the Cyperaceae) were borrowed from
Britton and Brown, Illustrated Flora of the Northern United States and Canada,
through the kindness of the trustees of the estate of Addison Brown. One fig-
ure (No. 1 of Group A) was borrowed from a Brooklyn Botanic Garden contribu-
tion of H. K. Svenson.

REPRINT NOTICE

The Bureau of Sport Fisheries and Wildlife is grateful to the U.S. Public
Health Service for permission to reprint its Bulletin No. 286, "A Guide and Key
to the Aquatic Plants of the 'Southeastern United States." When issued in
1944, this publication was very well received and the supply is now exhausted.
It has been available only in libraries of some State and Federal agencies, uni-
versities, and from private workers fortunate in having a copy in their possession.
Because of its continued usefulness, reprinting was arranged without change or
alteration to the original. The Bulletin will no doubt continue to serve biologists
of the Southeastern States concerned with aciuatic habitats for many years to
come.

u

CONTENTS

Fas«

Acknowledgments ii

Introduction 1

Glossary 1

Main keys 15

Key to groups 15

Key to Group A 15

Key to Group B 24

Key to Group C 25

Key to Group D 28

Key to Group E 38

Key to Group F 47

Introduction to catalog 66

Catalog of aquatic plants 67

Key to Alismaceae 72

Key to Gramineae 76

Key to Cyperaceae . 84

Principal works cons^ilted in compilation of guide 140

Index . 141

in

PHYSIOGRAPHIC
PROVINCES

0% the
SOUTHEASTERN
UNITED STATES

IV

A GUIDE AND KEY TO THE AQUATIC PLANTS
OF THE SOUTHEASTERN UNITED STATES

INTRODUCTION

The purpose of this compilation is to enable workers in the field, with
little knowledge of botany, to identify at least generically those fresh
water plants with which mosquito breeding is associated. It is hoped
that the keys and short notes with their accompanying illustrations will
obviate the use of the difficult and cumbersome manuals which are at
present the principal source of knowledge concerning the Southeastern
aquatic plants, and will enable the worker to make more accurate and
adequate evaluations of the area in which he is working.

The area considered in this guide, which in the text is often referred
to as "our territory" or "our range," includes the States of Tennessee,
North and South Carolina, Mississippi, Alabama, Georgia, and Florida.
States adjacent to these may be assumed to have similar aquatic floras,
but the range was thus limited because the above States are those with
which the authors are best acquainted. On the frontispiece map the
primary physiogi'aphic regions of these States are shown in outline.

A difficulty in preparing a list of the kind presented here is determin-
ing which plants to include. The principal criterion used has been the
possibility or likelihood of the plant's being associated with mosquito
breeding. Even this breaks down, for in times of very high waters dry
land plants like the common cocklebur may shelter larvae. Possibly
some of these plants, purposely omitted from the list, should have been
included, and undoubtedly there are unintentional omissions of plants
that can be found associated with mosquito production; but it is be-
lieved that on the whole the situations met within the Southeastern
States are covered.

GLOSSARY

In as large measure as possible the authors have utilized in the
keys parts of the aquatic plant most familiar to the general worker
and have used terminology not requiring a great knowledge of plant
morphology. But for the sake of exactness it was found necessary to
use some of the precise botanical terms. All of these, and some of
the better known designations, are included in the illustrated glossary
below.

Note. — Work was done at the Office of Malaria Investigations, Memphis, Tenn.

1

2 PUBLIC HEALTH BULLETIN NO. 2 86

The higher plants ordinarily are made up of roots, stems, leaves,
and in proper season flowers or fruits. Each of these presents itself
in the widest diversity of form and habit, and each is on occasion
lacking in some species. In most cases vegetative characters have
been used in the keys, as these characters are always present and are
best understood by the non-botanist. In some instances, however,
floral characters must be used to make clear separations in the keys.

The keys have been compiled from a variety of sources and have
been tested in the field and from herbarium material. They are of
the non-indented dichotomous type as this type is most economical
in printing. In each case two alternatives are offered, one of which
should fit best the plant in hand. The basis of the primary divisions
of the key is the growth habit of the plant. This means of division
is used because the habit of the plant has an important relationship
to its importance as harborage for mosquito larvae. Divisions in the
key are made in as great measure as possible on vegetative characters
as the layman is usually unfamiliar with the anatomy of the floral
organs. An illustrated glossary of both vegetative and floral char-
acters opens the way to a fuller working knowledge of the keys.

Desirable tools are a hand lens of about 10 magnifications and a
millimeter scale, as in some cases details which require magnification
are used in separating the species, and in many cases comparative
size is used. It is suggested that if in the process of using the key
some character seems ambiguous, the plant be looked for in both
divisions. If after keying and comparison wuth the illustrations there
is still doubt as to the identity of the plant, it should be checked
with the more adequate descriptions of the larger manuals.

Each genus of the main key is illustrated by a drawing of a repre-
sentative plant. The majority of these have been prepared especially
for this guide by Garnet W. Jex, United States Public Health Service,
but a large number have been borrowed from several publications.
The author-source of these borrowed figures has been acknowledged
elsewhere.

The nomenclature used in this guide is conservative and follows
the best present day usage. In many cases the scientific names differ
from those used by Small in his Manual of the Southeastern Flora,
and in most places these discrepancies have been noted in the text.

Roots are used in the keying in only a few instances. Stems are
not widely used except in the primary divisions of the keys. Whether
the stem is woody or herbaceous is of great importance but is usually
obvious. The habit of the stem, whether erect or reclining, lax or
rigid, is also important, as is the presence or absence of hairs or other
appendages.

Leaves show great diversity in many characters. The shape is
perhaps most important. The state of division of the leaf, whether

A GUIDE AND KEY TO AQUATIC PLANTS 3

compound or simple, dissected, lobed, or otherwise, is of only slightly less
importance. The manner of attachment, whether alternate, opposite,
or whorled, is a commonly used point of separation, as is the character
of the leaf margin, whether hairy, toothed, etc. Other characters also
much used are the nature of the apex of the leaf, the manner of vena-
tion, and such sensory characters as color, odor, and feel. Relative
size is, as stated before, often used. Leaves are used in the majority
of the key separations, and it is of primary importance that the leaf
terminology be learned.

Flowers are more diverse than other plant structures, and the lay-
man is often dismayed by the complex terminology. Only the
absolutely necessary terms are used in the keys of this guide. Typ-
ically a flower consists of a stalk {pedicel or peduncle) upon the summit
of which are borne several concentric whorls or cycles of floral parts.
The outermost whorl is the calyx, made up of the ordinarily green
sepals. Next outermost is the corolla, made up of petals which usually
give color to the plant. Unfortunately petals are often lacking, and
if only one whorl of accessory flower parts is present, they are termed
sepals, even though sometimes colored. Within the petals is one or
more whorls of pollen-bearing stamens, and within these is the inner-
most whorl consisting of one or more pistils which ultimately give rise
to the seed. Sometimes stamens and pistils are found only in separate
flowers, but usually they occur together. The stamens and pistils are
usually termed the essential flower parts in contrast to the accessory
sepals and petals. Flowers are borne either alone or in clusters known
as inflorescences. Several types of inflorescences are illustrated in the
glossary, small circles representing individual flowers, and lines the
stalks.

In using the key several floral characters are used, color and size
being of much importance. The shape and number of parts is also
important as is the type of inflorescence. Also used is the extent of
union of parts as sepals and petals are often partially or wholly united.

Two families of plants merit special attention as regards terminology.
These are the grasses, Gramineae, and the sedges, Cyperaceae. Both
are important and difficult aquatic groups. Below (figures 1 and 2)
are diagrams of the morphology of the two families. In recognizing
grasses the ligule of the leaf is of great importance. This structure,
present at the inner base of the leaf where it joins the leaf-sheath, varies
in size and nature but may usually be detected. The arrangement of
grass leaves in two ranks or rows up and down the stem is also of great
importance. Sedges may be distinguished by the absence of a ligule
and the three-ranked arrangement of the leaves.

The arrangement of the flowers in the two groups is similar in some
respects and different in others. Both have the small flowers or
florets grouped one to many in spikelets. In the grasses each spikelet

PUBLIC HEALTH BULLETIN NO. 2 86

f/oref

glumes

SPIKELET

■awn

■pdle^

■ le

mma-

FLORETS

¥^ LEAF

ARRANGEMENT

''' '""—leaf bUe
-ligule

fieafh

Figure 1. — A generalized diagram illustrating the morphology of grasses.

scale

SPIKELET

.stem

— leaf blade

I

-leaf shedfh

tubercle

dchene

■perianth
bristles

LEAF
ARRANGEMENT

Figure 2. — A generalized diagram illustrating the morphology ofisedges.

A GUIDE AND KEY TO AQUATIC PLANTS 5

bears at tlie base two chaff-like empty bracts called the glumes, and
each floret consists of two scales called the lemma and the palea with
essential parts inclosed. In the sedges all of the scales or bracts are
similar and are not designated by different terms. Important in
identifying the sedges is the nature of the fruit or achene. The size,
shape, presence or absence of a tubercle at the apex, the texture of the
surface, and the nature of the perianth-bristles are used. Typical
achenes are shown in the diagrams.

GLOSSARY OF BOTANICAL TERMS

Achene. — A small, dry, hard, indehiscent fruit.

Acuminate. — Tapering at the end (fig. 3).

Acute. — Terminating with a sharp point (fig. 4).

Adnate. — United with or adhering to.

Alternate. — Usually pertains to leaves. Not opposite each other but borne

singly at different levels on the stem (fig. 5) .
Annual. — A plant of only one year's duration.
Anther. — The pollen-bearing portion of a stamen (fig. 6) .

^Anther

Figure 3.

Figure 4.

Figure 5.

Figure 6.

Aristate. — Be">nng an awn or bristle at the tip (fig. 7).
Attenuate. — Slenderly tapering; long drawn-out (fig. 8).
Awn. — A bnstle-like appendage (fig. 7) .
Axil. — The angle formed by a leaf with the stem (ag. 9).
Axillary. — Borne in the axils of the leaves.
Biconvex. — Lenticular (fig. 10).

—Awn

Figure 7.

Figure 8.

Figure 9.

Figure 10.

6

PUBLIC HEALTH BULLETIN NO. 286

BiDENTATB. — Bearing two teeth at tip (fig. 11).

Bilateral. — Having, or arranged upon, two corresponding sides.

Blade. — The expanded portion of a leaf (fig. 12).

Bract. — A modified leaf usually subtending a flower or flowers (fig. 13).

Bractlet. — A small bract.

Caltx. — The outermost circle of flower parts; made up of sppals (fig. 14).

Blade

Figure 11.

Figure 12.

Figure 13.

] Calyx

Figure 14

Cancellate. — With a cellular-like surface (fig. 15).

Capsule. — A dry dehiscent fruit composed of more than one carpel.

Carpel. — A simple pistil or one of the parts of a compo.und pistil (fig. 16).

Ciliate. — Fringed with hairs (fig. 17).

Ciliolate. — Minutely ciliate.

Claw. — The contracted stalk-like base of a petal (fig. 18).

Stigma-
Style.

Figure 15.

Figure 17.

Compound. — Composed of two or more similar parts united to form one whole;

for instance, a leaf (fig. 19) . ^
Cordate. — Heart-shaped with the tip upward (fig, 20).
Coriaceous. — 'With leathery texture.
CoRM. — A hard, bulb-like base of a stem (fig. 21).
Corolla. — The inner circle of flower parts: made up of petals which are often

colored and showy (fig. 22)

'Leaflet
Figure 19.

Figure 20.

Figure 21.

Corolla

Figure 22.

A GUIDE AND KEY TO AQUATIC PLANTS 7

Corolla-tube. — Tubular structure formed by united petals (fig. 23).

Corymb. — A type of flower cluster with a flat top (fig. 24).

Corymbose. — With a corymb-like inflorescence.

Crown. — In Hymenocallis a white membrane uniting the filaments. (See fig. 17

of Group E.)
CuNEATE. — Wedge-shaped (fig. 25).
Deciduous. — Falling off.

Decumbent. — Reclining but with the summit of the plant ascending.
Decurrent. — Extending or running down on another structure, as a leaf on a

stem or a tubercle on an achene (fig. 26) .

Corolla-
tube

Figure 23.

Figure 24.

Figure 25.

Figure 26.

Deltoid. — 'Shaped like an equilateral triangle or the Greek letter delta (fig. 27).
DiCHOTOMOus. — Forking regularly by twos (fig. 28).

Dissected. — Cut into numerous very fine segments or divisions (fig. 29).
Distichous. — Coming off in two ranks (fig. 30).

Figure 27.

Figure 28.

Figure 29.

Figure 30.

Divaricate. — Diverging at a wide angle (fig. 31).

Dorsal. — Surface of an organ away from the central axis of the plant.

EcHiNATE. — Prickly.

Elliptic. — Pertains to shape (fig. 32) .

Emergent. — Rooted to substratum; erect and extending upward out of water

(fig. 33).
Emersed. — Standing above and out of water (fig. 33) .
Entire. — Without teeth or other irregularities along the margin (fig. 32).

Emersed

Submerged

Figure 31.

Figure 32.

Figure 33.

Figure 34.

8

PUBLIC HEALTH BULLETIN NO. 286

Equitant. — Pertaining to leaves; coming ofT in two ranks, making the base

appear flattened (fig. 35).
Erose. — Appearing as if gnawed (fig. 36).
Fascicle. — A cluster or bundle (fig. 37).
Filament. — The part of the stamen which supports the anther (fig. 38).

Figure 35.

Figure 36.

Figure 37.

Filament

Figure 38.

Filiform. — Like a thread; long, slender, and round (fig. 39).

Flexuous. — Alternately bent or twisted in different directions (fig.

Floret. — A small flower of the grasses, (fig. 1).

Foliaceous. — Leaf-like.

Fusiform. — Spindle-shaped (fig. 41).

Gibbous. — Swollen on one side (fig. 42).

40).

Figure 39.

Figure 40.

Figure 41.

Figure 42.

Glabrous. — Without hairs.

Glaucous. — Covered with a whitish or silvery bloom.

Globose. — Spherical (fig. 43).

Glume.— A chaff-like bract at the base of a spikelet in the grasses (fig. 1).

Granular. ^ — Appearing as if covered by small grains; with a grainy texture.

Hastate. — Like sagittate but with lobes diverging (fig. 44).

Head. — A' dense cluster of sessile or almost sessile flowers borne on a very short

axis (fig. 45).
Herb.^ — A plant with no persistent woody stem above the ground.
Herbaceous. — Without woody tissues.
Hispid. — Stiff-hairy.
HispiDULous. — Minutely stiff-hairy.
Hypanthium. — Portion of the united calyx investing the fruit (fig. 46).

Figure 43.

Figure 44.

Figure 45.

Hypanfhium
Figure 46.

A GUIDE AND KEY TO AQUATIC PLANTS

9

Htpogtnum. — In Scleria, a structure underneath and supporting the ovary or

fruit.
Imbricate. — Spirally overlapping (fig. 47).

Incised. — Cut sharply, irregularly, and more or less deeply (fig. 48).
Indehiscent. — Remaining closed at maturity.
Inflated. — Dilated or distended.

Inflorescence. — The flowering part of a plant; a cluster of flowers.
Involucre. — A collection of bracts surrounding a flower cluster or head or

sometimes a solitary flower.
Involute. — RoUed inwardly toward the midrib (fig. 49) .
Irregular. — Showing inequality in the arrangement of the floral parts; usually

bilaterally symmetrical.
Keeled. — Possessing a central ridge as a boat (fig. 50).

Figure 47.

Figure 48.

Figure 49.

Figure 50.

Lacerate. — Irregularly cut as if torn (fig. 51).

Lamelliform. — Plate-like.

Lanceolate. — Shaped like a spear-head, broadest near base, tapering to apex,

and several times as long as broad (fig. 52) .
Leaflet. — One of the segments of a compound leaf (fig. 19).
Lemma. — The lower of the two bracts enclosing each floret in the grasses (fig. 1).
Lenticular. — Lens-shaped, biconvex (fig. 10).
LiGULE. — A hairy or scarious projection at the point on the inner surface of a

grass leaf where the sheath and blade meet (fig. 1) .
Linear. — Long and narrow and with parallel sides (fig. 53).
LoBED. — With projection or divisions (fig. 54).

M

Lobe

Figure 51.

Figure 52.

Figure 53

Figure 54.

10

PtJBLiC HEALTH BULLETIN NO. 286

Longitudinal. — Along the long axis of a structure.
Membranous. — With membrane-like texture.

Midrib. — Main rib of normal leaf running from base to apex (fig. 55).
MucRONATE. — Ending in an abrupt, fine, slender tip (fig. 56).
Nodes. — The places on the stems that normally bear leaves (fig. 57) .
Nodose. — Knotty or knobby.

Oblanceolate. — Lanceolate in outline but with the broadest part toward the
apex (fig. 58).

Midrib

Figure 55.

Figure 56.

Nodes

Figure 57,

Figure 58.

Oblong. — Longer than broad and with nearly parallel sides (fig. 59).

Obovate. — Ovate in outline but with the broadest portion toward the apex

(fig. 60).
Obpyramidal. — Shaped like a pyramid with the broad end uppermost (fig. 61).
Obtuse. — Blunt or rounded at the tip (fig. 62).

Figure 59.

Figure 60.

Figure 61.

Figure 62.

Ogre A. — A tubular sheath present on the stem just above the base of the leavet
of docks and smartweeds. It is formed of -the fused stipules (fig. 63).

OcREOLAE. — Small ocrea-like structures on the rachis of the flower clusters
in Polygonum.

Opposite. — Coming ofif opposite each other at the same level on the axis (fig. 64).

Orbicular. — Circular or round (fig. 65).

Ovary. — The basal portion of the pistil in which the seeds or ovules are borne
(fig. 66).

Ocrea \J^

Ovary.

Figure 63.

Figure 64. Figure 65.

Figure 66.

A GUIDE AND KEY TO AQUATIC PLANTS

11

Ovate. — Having an outline like that of an egg, with the broadest part downward

(fig. 67).
Ovoid. — Egg-shaped; see ovate.

Panicle. — An irregularly compound flower cluster with stalked flowers (fig. 68).
Paniculate. — With a panicle-like inflorescence.
Papillose. — Bearing small pimple-like projections.
Pedicel. — The stalk of a single flower (fig. 69).

Peduncle. — The stalk which supports a flower cluster or a solitary flower.
Peltate. — Petiole attached not at margin of leaf but in the middle of the lower

surface (fig. 70).

Figure 67.

Figure 68.

Pedicel

Figure 69.

Figure 70.

Perennial. — A plant of more than two years' duration.

Perianth. — The calyx and corolla taken together (fig. 71).

Perianth-bristles. — Rudimentary perianth parts in sedges (fig. 2).

Perigynium. — The inflated sac which contains the ovary or fruit of Carex.

Persistent. — Not falling off or away.

Petal. — A member of the inner circle of flower parts; often colored and showy

(fig. 72).
Petiole. — The stalk of a leaf (fig. 73).
Pistil. — The seed-bearing part of a flower (fig. 74).

Perianth

Figure 71.

Peial

Figure 72.

Petiole

Figure 73.

Figure 74.

12

PUBLIC HEALTH BULLETIN NO. 286

Pistillate. — With or pertaining to pistils.

Pollen. — The usually yellow grains contained in the anther.

Procumbent. — Lying or crawling along the ground.

Proliferous. — Producing ofiF-shoots.

PuBERULENT. — With minute hairs.

Pubescent. — Covered with hairs, often short and downy (fig. 75).

Punctate. — With small dots, which can often be seen only with a lens (fig. 76).

Raceme. — A flower cluster with the flowers stalked and coming off a common

and more or less elongated axis (fig. 77).
Rachilla. — A secondary inflorescence rachis.
Rachis. — The axis of an inflorescence (fig. 77) .

Ray-flowers. — The flat marginal flowers of the head in the Compositae.
Recurved. — Curved backwards or toward base.
Regular. — Pertaining to flowers; flowers radially symmetrical.
Reniform. — Kidney -shaped (fig. 78).

^

^

\

Rachis —

N

/'

Figure 75.

Figure 76.

Figure 77.

Figure 78.

Reticulate. — With a network-like surface (fig. 79).

Revolute. — Appearing as if rolled back from the margins (fig. 80).

Rhizome. — A prostrate or underground stem.

Rosette. — With the leaves clustered symmetrically around the base of the stem

or scape (fig. 81).
Sagittate. — Like an arrowhead, with the lobes turned downward (fig. 82).

Figure 79.

Figure 80.

Rosette^

Figure 81.

Scape

Figure 82.

A GUIDE AND KEY TO AQUATIC PLANTS

13

Scabrous. — Rough.

Scape. — A naked peduncle rising from the ground (fig. 81).

Sepal. — A member of the outermost circle of flower parts (fig. 83) .

Septate. — Possessing partitions or septa.

Septum. — A partition (pi. septa).

Serrate. — Toothed like a saw (fig. 84.)

Serrulate. — Minutely sharp-toothed.

Sessile. — Without a'stalk of any kind. May refer to leaves, bracts, flowers, or
flower clusters.

Setose. — Bristly.

Shrub. — A woody plant smaller than a tree and often with several stems.

Simple. — Not compound.

Sinus. — A cleft or recess between two lobes (fig. 85) .

Spathe. — Leaf-like structure more or less enclosing a fleshy inflorescence, par-
ticularly in the Araceae (fig. 86).

Figure 83.

Figure 84.

Sinus
Figure 85.

Figure 86.

Spatulate. — Pertains to shape (fig. 87).

Spike. — A flower cluster with the flowers sessile along a common more or less

elongated axis (fig. 88).
Spikelet. — A small or secondary spike as in the grasses and sedges (fig. 1 and 2).
Spinulose. — Minutely spiny.

Spur. — A hollow sac-like or tubular extension of some part of a flower (fig. 89).
Stamen. — The pollen-bearing organ of the flower (fig. 90) .

Figure 87.

Figure 88.

Figure 89.

Figure 90.

14

PUBLIC HEALTH BULLETIN NO. 286

Staminate. — With or pertaining to stamens.

Stigma. — The sticky portion of the pistil, usually tenninal, upon which the

pollen is deposited (fig. 91).
Stipe. — A stalk.
Stipitate. — Possessing a stipe.
Stipule. — An appendage at the base of the petiole of a leaf; normally occurring

in pairs (fig. 92).
Stoloniferous. — Producing runners from the base.
Style. — The part of the pistil connecting the stigma and the ovary. Generally

it is attenuated (fig. 91).
Style-appendages. — Petaloid wings on the styles of Iris.
SuBCORDATE. — Somewhat heart-shaped (fig. 93).
SuBGLOBOsB. — Almost spherical.
SuBTENP. — To come out below.
Subulate. — Shaped like an awl (fig. 94).

Sfigma
Style

Stipule

i

Figure 91.

Figure 92.

Figure 93.

Figure 94.

Tomentose. — Densely woolly.

Tree. — A large single-stemmed woody plant; has been defined as being over 6

meters tall and over 1 decimeter in diameter.
Truncate. — Ending abruptly as if cut off (fig. 95).
Tubercle. — An enlarged, persistent style base often found on the .summit of

the fruits of sedges (fig. 96).
Turbinate. — Top-shaped or conidal with the broad end uppermost (fig. 97).
Umbel. — A type of flat-topped flower cluster (fig. 98).

Figure 95.

Figure 96.

Figure 97.

Figure 98.

Undulate. — With a wavy margin (fig. 99) .
Villous. — Possessing long soft hairs.

Whorl. — An arrangement of leaves or other parts in which they come off several
at the same level around the stem (fig. 100).

Figure 99.

Figure 100.

1.
1.

3.
3.

KEY TO GROUPS

Shrubs or trees Group A, p. 15.

Vines or herbs 2.

2. Vines Group B, p. 24.

2. Herbs 3.

Plants free-floating Group C, p. 25.

Plants attached to substratum 4.

4. Plants floating, submerged, or forming mats on Group D, p. 28.

or just above the surface of the water.

4. Plants erect and emergent; rooted to the sub- 5.
stratum and extending upward out of the
water.

Plants without leaves or with long narrow leaves at Group E, p. 38.
least 12 times as long as broad and usually grass or
rush-like.

Plants with shorter, broader leaves Group F, p. 47.

KEY TO GROUP A

1. Leaves very narrow, often needle-like 2.

1. Leaves with expanded blades 4.

2. Shrub with yellow flowers (fig. 1) Hypericum, p, 123.

2, Cone-bearing trees 3.

3, Needles long and two to several in fascicles (fig. 2) Pinus, p. 68.

3. Needles shorter, arranged in two ranks along twig, or Taxodium, p. 68.
sometimes appressed to twig; not in fascicles (fig. 3).

Figure 1.

Figure 2.

Figure 3.

15

16 PUBLIC HEALTH BULLETIN NO. 286

4. Leaves opposite 5.

4. Leaves alternate or borne irregularly 13.

5. Leaves simple 6.

5. Leaves compound 11.

6. Leaves lobed (fig. 4) Acer, p. 122.

6. Leaves not lobed 7,

7. Shrubs, often very low; leaves with tiny semi trans- Hypericum, p. 12i/.

parent dots visible with hand-lens; flowers showy

yellow (fig. 5).

7. Shrubs or small trees; leaves without dots; flowers not 8.

showy yellow.

FiGUBE 4.

Figure 5.

8. Stems sturdy and erect, leaves elliptic to wider; 9.

flowers not showy purplish.
8. Stems weakly arching; leaves lanceolate; flowers Decodon, p. 125.
showy purplish (fig. 6) .
9. Leaves remotely toothed, acuminate at apex; flowers Forestiera, p. 133.

appearing before the leaves (fig. 7).
9. Leaves entire, acute but not acuminate; flowers appear- 10.
ing after leaves are on the plant.

Figure 6.

Figure 7.

A GUIDE AND KEY TO AQUATIC PLANTS

17

10. Flower clusters conspicuous because of large, leaf- Pinckneya, p. 138.

like, pink sepals (fig. 8).
10. Flowers white in stalked globose clusters; fruits Cephalanthus, p. 138.
aggregated in spherical clusters_(fig. 9).

FlGtJRE 8.

Figure 9.

11. Trees 12.

11. Shrub (fig. 10) Sambucus, p. 138.

12. Leaflets usually 3; very prominently toothed Acer, p. 122.

(fig. 11).

12. Leaflets usually more than 3; not prominently Fraxinus, p. 133.

toothed (fig. 12).

Figure 10.

Figure 11.

Figure 12.

18 PUBLIC HEALTH BULLETIN NO. 286

13. Leaves simple 17.

13. Leaves compound 14.

14. Trees 16.

14. Shrubs _. 15.

15. Plant thorny; leaflets not over 9 usually 7 or 5 (fig 13) - Rosa, p. 1 19.
15. Plant not thorny; leaflets more than 11 (fig. 14) Amorpha, p. 120.

xVs

Figure 13.

Figure 14.

16. Leaflets many and small, usually 12-22; tree Gleditsia, p. 120.

prominently thorny (fig. 15).
16. Leaflets fewer and large, usually 9; tree not Carya, p. 112.

thorny (fig. 16).

Figure 15.

Figure 16.

17. Leaves aromatic when crushed 18.

1 7. Leaves not aromatic when crushed 22.

18. Leaves with small, orange wax glands on Myrica, p. 112.

lower surface when examined with lens;

leaves usually prominently toothed (fig. 17).
18. Leaves without wax glands below; leaves 19.

entire or nearly so.

A GUIDE AND KEY TO AQUATIC PLANTS

19

19. Leaves, at least the younger ones, densely hairy or Persea, p. 124.

wooly beneath (fig. 18).
19. Leaves not wooly beneath, glabrous or nearly so 20.

Figure 17,

Figure 18.

20. Leaves silvery (glaucous) beneath (fig. 19).- Magnolia, p. 119.

20. Leaves not silvery beneath 21.

21. Fruit oval, longer than broad; leaves mostly over Benzoin, p. 124.

6 cm. long (fig. 20).

21. Fruit globose, about as long as broad; leaves mostly Glabraria, p. 124.

less than 6 cm. long (fig. 21).

Figure 19.

Figure 20.

Figure 21.

20 PUBLIC HEALTH BULLETIN NO. 286

22. Leaves distinctly toothed 27.

22. Leaves entire or nearly so 23.

23. Trees with swollen bases; fruit a drupe, longer than Nyssa, p. 130.
wide (fig. 22).

23. Shrubs or small trees; fruit, if not dry, globose 24.

24. Leaves entire; fruit dry 25.

24. Leaves usually with a few remote teeth above Ilex, p. 121.
the middle or at least bristle-tipped; fruit
a red or black berry (fig. 23) .

Figure 22.

Figure 23.

25. Leaves leathery, broad, and with a conspicuous vein Desmothamnus, p. 132.

running just inside the margin (fig. 24).
25. Leaves not leathery or broad, but oblong and with no 26.
intramarginal vein.

26. Flower clusters lateral; fruit not winged Cyrilla, p. 121.

(fig. 25).
26. Flower clusters terminal; fruit winged (fig. Cliftonia, p. 121.
26).

Figure 24.

Figure 25.

Figure 26.

A GUIDE AND KEY TO AQUATIC PLANTS

27. Branches spiny : fruit apple-like (fig. 27) Crataegus, p. 120.

27. Branches not spiny; fruit not apple-like 28.

28. Bark falling away in reddish, papery layers Betula, p. 113.

(fig. 28).
28. Bark not falling away in papery layers 29.

21

x/3
Figure 27.

Figure 28.

29. Low, brittle shrub with wood lighter than cork; green Stillingia, p. 121.

parts with a milky sap (fig. 29).
29. Shrubs or trees, not brittle or lighter than cork; sap 30.
not milky.

30. Leaves leathery; evergreen; flowers showy, Gordonia, p. 124.

white, large (6 cm. across) : tree (fig. 30).
30. Leaves not leathery or evergreen (except one 31.
species of low-shrubby Leucothoe); flowers
not individually large.

Figure 29.

Figure 30.

22

PUBLIC HEALTH BULLETIN NO, 286

31. Small trees or shrubs; flowers not white or showy and 32.

appearing in early spring.

31. Shrubs; flowers white in showy racemes, appearing 34.
usually in late spring or summer.

32. Leaves over 4 times as long as broad (fig. 31). _ Salix, p. 112.

32. Leaves scarcely over 2 times as long as broad.. 33.

33. Buds covered with overlapping scales; fruit warty Planera, p. 113,

(fig. 32).

33. Buds with a single scale; fruit cone-like (fig. 33) AInus, p. 113.

XI

Figure 31.

FiGUEE 32.

Figure 33.

A GUIDE AND KEY TO AQUATIC PLANTS

23

34. Petals not united; anthers not awTied 35.

34. Petals united to form tubular corolla; anthers Leucothoe, p. 132.
with prominent awns at tip (fig. 34) .
35. Sepals not pubescent or only slightly so; fruit a linear, Itea, p. 119.

2-grooved capsule; leaves elliptic (fig. 35).
35. Sepals copiously pubescent; fruit a subglobose, 3- Clethra, p. 132.
valved capsule; leaves cuneate (fig. 36).

24

PUBLIC HEALTH BULLETIN NO. 286

KEY TO GROUP B

1. Leaves compound (fig. 1) Ampelupsis, p. 122.

1. Leaves simple 2.

2. Leaves with several veins running from base to Smilax, p. 109.

apex; stems often thorny (fig. 2).
2. Leaves without several veins running from base 3.

to apex; stems not thorny.

Figure 1.

3. Stems woody . 4.

3. Stems herbaceous 5.

4. Leaves leathery, toothed only near apex (fig.)3_ Ampelothamnus.p. 132.
4. Leaves not leathery, entire or with wavy edge Berchemia, p. 122.
(fig. 4)

Figure 3.

Figure 4.

A GUIDE AND KEY TO AQUATIC PLANTS

25

5. Leaves alternate, not prominently toothed, subcordate Breweria, p. 134.

at the base (fig. 5).
5. Leaves opposite, with wavy margins or angularly Mikania, p. 139.

toothed (fig. 6).

X /o /:

Figure 5.

Figure 6.

KEY TO GROUP C

1. Plants very small ; seldom over a centimeter along any 2.

dimension,
1. Plants large; usually measuring at least 0.5 decimeter 8.
along some dimension.
2. Plant body dichotomously 2-lobed, or repeatedly 3.

dichotomously branched.
2. Plant body not dichotomously branched and if 2- 4.
lobed not equally so.
3. Divisions of plant body fine and many; plant body Riccia, p. 67.

usually floating below surface (fig. ]).
3. Divisions of plant body coarse, 2-lobed; floating on Ricciocarpus, p. 67.
surface (fig. 2).

xl7:

Figure 1.

Figure 2.

26

PUBLIC HEALTH BULLETIN NO. 286

4. Plants floating on surface 5.

4. Plants floating just below water surface; plant Wolffiella, p. 103.
body made up of a clump of short filaments
(fig. 3).

5. Plant body of small overlapping scales (fig. 4) Azolla, p. 67.

5. Plant body simple or compound, made up of rounded 6.
floating leaves.

X I'/?

xl'/?

Figure 3.

FlOURE 4.

6. Plants simple, extremely minute, appearing as Wolffia, p. 103.

grains on surface of water (fig. 5) .
6. Plants compound, made up of several rounded- 7.
oblong disk-like bodies, floating on surface of
water.
7. Plant body inconspicuously nerved, rootlets 1 per disk Lemna, p. 103.

(fig. 6).
7. Plant body conspicuously nerved, rootlets 2 to several Spirodela, p. 104.
per disk (fig. 7).

X 8

FlQURB 5.

X I'll

Figure 6.

Figure 7.

A GUIDE AND KEY TO AQUATIC PLANTS

27

8. Leaves broad and blade-like, sometimes inflated 9.

near base.

8. Leaves (plant body in Riccia') narrow or finely 11.
divided.

9. Leaves large and dilated with inflated petioles (fig. 8) . Eichhornia, p. 107.

9. Leaves normally expanded 10.

10. Leaves wide to the base, without petioles (fig. 9). Pistia, p. 103.

10. Leaves mostly differentiated into blades and Limnobium, p. 76.
petioles (fig. 10).

x'/6

X 74

Figure 8.

Figure 9.

x'/s

28

PUBLIC HEALTH BULLETIN NO. 286

11. Plant body repeatedly dichotomously branched (fig. 1). Riccia, p. 67.
1 1 . Leaves not dichotomously branched 12.

12. Leaves entire not dissected or bearing blad- Anacharis, p. 75.

ders, and whorled (fig. 11).
12. Leaves dissected and bearingjbladders (fig. 12) _ Utricularia, p. 137.

Figure 12.

KEY TO GROUP D

1. Vegetative body formed of floating stenas without leaves. 2.

1. Vegetative body formed of stems and leaves 4.

2. Branches of stem bearing small bladders; Utricularia, p. 137.
flowers showy, purple (fig. 1).
[ 2. Stem or branches not bearing bladders; 3.
flowers absent or inconspicuous.
3. Plant body made up of smooth, proliferating stems Eleocharis. p. 88.

(fig. 2).
3. Plant body made up of stems bearing whorled, brittle Chara, p. 67.
branches (fig. 3).

Figure 1.

Figure 2.

FlQUBB 3.

A GUIDE AND KEY TO AQUATIC PLANTS

29

4. Plants bearing linear, sometimes long and 5.
ribbon- or thread-like submerged leaves,
or compound submerged leaves with nar-
row divisions; plants often entirely sub-
merged, with or without floating or emersed
leaves.
4. Plants not bearing submerged linear, ribbon- 26.
or thread-like leaves or narrowly segmented
submerged leaves; plants often not entirely
submerged; submerged leaves, if any,
similar to the floating or emersed leaves.
5. Submerged leaves bearing bladders; flowers irregular,

showy yellow or purple (fig. 4)
5. Submerged leaves not bladder bearing; flowers regular.
6. Submerged leaves compound, made up of

narrow segments or leaflets.
6. Submerged leaves simple, made up of a single 13.
narrow blade.

7. Submerged leaves with a central axis 8.

7. Submerged leaves irregularly forking 11.

8. Submerged leaves scattered along almost the 9.
entire length of the stem; flower stalks not
inflated.
8. Submerged leaves gathered along a few centi-
meters of the stem; flower stalks inflated
(fig. 5).

Utricularia, p. 137.

6.

7.

Hottonia, p. 132.

Figure 4.

Figure 5.

30

PUBLIC HEALTH BULLETIN NO. 2 86

9. Submerged leaves whorled, stems usually very lax Myriophyllum, p. 129.
(fig. 6). ^

9. Submerged leaves scattered, stems not so lax 10.

10. Submerged leaves with simple divisions Proserpinaca, p. 129.

(fig. 7).
10. Submerged leaves with leaflets again divided Neobeckia, p. 119.
(fig. 8).

L^^^^

^/.

Figure 6.

Figure 7.

Figure 8.

11. Submerged leaves alternate or irregularly borne Ranuneulus, p. 118.

(fig. 9).
11. Submerged leaves borne opposite each other on stem 12.
or whorjed.

12. Submerged leaves opposite; leaflets not Cabomba, p. 117.

toothed (fig. 10).
12. Submerged leaves whorled; leaflets minutely Ceratophyllum, p. 116.
toothed on one edge (fig. 11).

A GUIDE AND KEY TO AQUATIC PLANTS

31

13. Submerged leaves long and ribbon-like, at 14.

least 3 mm. wide.
13. Submerged leaves not ribbon-like; often 17.

thread-like but if wider than 3 mm., less

than 2.5 cm. long.

14. Leaves all borne from one point 16.

14. Leaves scattered along the stem 15.

15. Leaves without midribs evident when exam- Heteranthera, p. 106.

ined against transmitted light; flowers

yellow (fig. 12).
15. Leaves with midribs evident when examined Potamogeton, p. 69.

against light; flowers inconspicuous, not

yellow (fig. 13).

Figure 12.

Figure 13.

16. Leaf, when examined with hand lends, showing a cen- Vallisneria, p. 75.

tral dense and a peripheral less dense zone (fig. 14).
16. Leaf, when examined with hand lends, not showing AHsmaceae, p. 72.

zones (fig. 15).

Figure 14.

Figure 15.

I7. Leaves all from a hardened base or from 'a Isoetes, p. 68.
single point; base of leaves with spore-sacs
(fig. 16)

17. Leaves borne along stem "l8.

18. Leaves opposite or whorled 19.

18. Leaves alternate or singly borne or crowded 24.

19. Leaves opposite, but sometimes appearing 20.
whorled because of fascicles of leaves in the
axils of the opposite leaves.
19. Leaves whorled 23.

32

PUBLIC HEALTH BULLETIN NO. 2 86

20. All leaves long and narrow 21.

20. Upper leaves shorter and broader (fig. 17) Callitriche, p. 121.

Figure 16.

Figure 17.

21. Plants lax, not rooting along the stem 22.

21. Plants stiflF, rooting along the stem; leaves

stiff and often in fascicles (fig. 18). Juncus, p. 107.

22. Leaves with dilated bases (fig. 19) Najas, p. 71.

22. Leaves with narrow bases (fig. 20) Zannichellia, p. 71.

Figure 18.

Figure 19.

Figure 20.

A GUIDE AND KEY TO AQUATIC PLANTS

33

23. Leaves 4-6 in whorls, blades very narrow; Sclerolepis, p. 139.

flowers conspicuous, purple (fig. 21)
23. Leaves usually 3 in whorls (sometimes 4) ; Anacharis, p. 75.

flowers minute and inconspicuous (fig. 22).

Figure 21.

Figure 22.

24. Leaves borne separately along stem; flowers incon- 25.

spicuous.
24. Leaves crowded on stem; flowers 3-petaled, pink and Mayaca, p. 104.
fairly conspicuous (fig. 23).

25. Leaf-base apparently inflated (fig. 24) Ruppia, p. 71.

25. Leaf-base narrow, sometimes with stipules Potamogeton, p. 69.
(fig. 25).

Figure 23.

Figure 24.

Figure 25.

34

PUBLIC HEALTH BULLETIN NO. 286

26. Leaves in rosettes which float on the surf ace of the water. 27.
26. Leaves not in rosettes floating on the surface of the water. 28.

27. Petioles of leaves greatly inflated (fig. 26) Eichhornia, p. 107.

27. Petioles not inflated (fig. 27) Limnobium, p. 76.

Figure 26.

Figure 27

28.

28.

30.
30.

Leaves arising from points along a horizontal stem, 29.
this stem being either buried under the substratum
or lying procumbent along it.
Leaves from lax stems which float in the water with 34.
the leaves.

29. Leaves peltate 30.

29. Leaves not peltate 32.

Leaves round 31.

Leaves elliptic, the petiole and under surface coated Brasenia, p. 117.
with a thick jelly-like material (fig. 28).

31. Leaves small, about 8 cm. in diameter or less; Hydrocotyle, p. 130.

toothed or lobed (fig. 29).
31. Leaves large; more than 20 cm. in diameter; Nelumbo, p. 117.
margins entire and impossible to wet leaf
(fig. 30).

Figure 28.

x'/2
Figure 29.

Figure 30.

A GUIDE AND KEY TO AQUATIC PLANTS

35

32. Leaves small, mostly less than 15 cm. long, heart- Nymphoides, p. 134.
shaped; flowers white and less than 2.5 cm. across
(fig. 31).
32. Leaves large, mostly more than 15 cm. long; flowers 33.
white or yellow, more than 5 cm. across.

33. Flowers white; leaf-blade round (fig. 32) Nymphaea, p. 117.

33. Flowers yellow; leaf-blade longer than wide, Nuphar, p. 116.
or approaching an orbicular shape (fig. 33).

Figure 31.

Figure 32.

Figure 33.

34. Leaves round, often peltate; the long petiole attached Hydrocotyle, p. 130.

near center of leaf (fig. 34) .

34. Leaves usually longer than broad ; petiole, if present, 35.
not attached at center of leaf.

35. Leaves broadened and often clasping at the 36.
base.

35. Leaves narrowed at the base 38.

36. Plants aromatic when crushed; flowers blue (fig. 35) __ Hydrotrida, p. 135.

36. Plants not aromatic when crushed; flowers white 37.

Figure 35.

36

PUBLIC HEALTH BULLETIN NO. 2 86

37. Stem finely pubescent; flowers 3-4 mm. long Herpestris, p. 135.

(fig. 36).
37. Stem not finely pubescent; flowers not more Micranthemum, p. 136.

than 1.5 mm. long (fig. 37),

Figure 36.

38. Leaves opposite 39.

38. Leaves alternate 40.

39. Flowers solitary in the axils of the leaves; Ludwigia, p. 126.

leaves less than 3.5 cm. long (fig. 38).

39. Flowers in stalked head-like spikes; leaves Alternanthera, p. 115.

over 3.5 cm. long (fig. 39).

A GUIDE AND KEY TO AQUATIC PLANTS

37

40. Leaves grass-like, continued as a sheath below base of Hydrochloa, p. 82.

blade (fig. 40).
40. Leaves not grass-like and not continued as a sheath be- 41.
low the base of the blade.

41. Stems with a sheath (ocreae) just above attach- Polygonum, p. 114.
ment point of leaf; flowers individually small,
white to pink (fig. 41)
41. Stems with no sheaths __ 42.

Figure 40.

Figure 41.

42. Flowers large, showy yellow; fruit a 4-angled capsule Jussiaea, p. 128.

(fig. 42).
42. Flowers small, inconspicuous; fruit a 3-angled nutlet Proserpinaca, p. 129.

(fig. 7).

38 PUBLIC HEALTH BULLETIN NO. 286

KEY TO GROUP E

1. Plants without leaves, consisting only of naked stems, 2.
sometimes with bladeless leaf sheathes, often bearing
a flower cluster at or near top.

1 . Plants bearing leaves 12.

2. Plants surmounted by a flower or fruit clus- 3.
ter.

2. Plants without flowers 7.

3. Flower cluster terminal 4.

3. Flower cluster appearing lateral with stem extending 6.
*beyond.

4. Leaf -sheaths present; flower cluster consisting 5.
of groups of flowers concealed by overlap-
ping scales.
4. No leaf-sheaths present; flower cluster con- Utricularia, p. 137.
sisting of 1 to several showy, irregular, yel-
low, or purple blossoms (fig. 1) .
5. Leaf-sheaths present only at base of stem; flowers in Eleocharis, p. 88.

in one group (fig. 2).
5. Leaf-sheaths scattered along stem; flowers in several Fuirena, p. 93.
groups (fig. 3).

XI

xl

Figure 1.

Figure 2.

Figure 3.

A GUIDE AND KEY TO AQUATIC PLANTS

39

6. Flowers or fruits hidden by overlapping scales Scirpus, p. 91.

(fig. 4).
6. Flowers or fruits individually manifest; parts Juncus, p. 107.

in threes (fig. 5).

x'/2

x/6

Figure 4. Figure 5.

7. Stems round in cross-section 8.

7. Stems angled in cross-section 10.

8. Stems large and long (1 meter or more) Scirpiis, p. 91.

8. Stems shorter 9.

9. Sheaths at base of stem with edges united to form tube Eleocharis, p. 88.

(fig. 6).
9. Sheaths at base of stem merely overlapping (fig. 7)... Juncus, p. 107.

X I

Figure 6.

Figure 7.

40

PUBLIC HEALTH BULLETIN NO. 286

11.
11.

13.
13.

15.

15.

10. Stems 4-angled Eleocharis, p. 88.

10. Stems 3-angled 11,

Stems long {% meter or more) Scirpus, p. 91.

St^ms shorter Eleocharis, p. 88.

12. Leaves all basal or from one pojnt 13.

12. Leaves distributed along stem 24.

Leaves round 14.

Leaves flattened 15.

14. Leaves from enlarged, spore-containing bases Isoetes, p. 68.

(fig. 8).
14. Leaves (in reality stems) not from enlarged, Eleocharis, p. 88.
spore-bearing bases; bases with a tubular
sheath (fig. 6).
Plants small, mostly under 1 dm. tall; leaves filiform, Myosurus, p. 118.

or very narrowly linear (fig. 9).
Plants mostly over 1 dm. tall; leaves more broadly 16.
linear.

Figure 8.

FlQDRE 9.

A GUIDE AND KEY TO AQUATIC PLANTS 41

16. Leaves keeled or folded 17.

16. Leaves flat and not keeled 19.

17. Plants aromatic when cru.shed (fig. 10) Acorus, p. 102.

17. Plants not aromatic 18.

18. Flowers violet, over 3 cm. across; leaves equit- Nemastylis, p. 110.
ant at base; that is coming in two ranks,
making the base of the plant appear flat-
tened (fig. 11).

18. Flower inconspicuous and hidden by overlap- Cyperus, p. 87.
ping scales (fig. 12).

Figure 10.

Figure 11.

x/z

Figure 12.

42

PUBLIC HEALTH BULLETIN NO. 286

19. Leaves equitant at base; that is, coming in two ranks 20.
making the base of the plant appear to be flattened.

19. Leaves coming out from all sides of base 21.

20. Leaves large (1 cm. wide or wider); flowers Iris, p. 110.

very showy (fig. 13.)
20. Leaves smaller, rigid; small yellow flowers Xyris, p. 104.
gathered in dense heads at top of naked
stalk, each subtended by a scale-like bract
(fig. 14).

Figure 14.

A GUIDE AND KEY TO AQUATIC PLANTS

43

21, Leaves arising from a bulb 23.

21. Leaves not arising from a bulb 22.

22. Leaves from base of scape bearing button- Eriocaulon, p. 106.
like whitish heads of minute flowers; roots
with cross-constrictions (fig. 15).
22. Leaves from base of scape bearing evident Sagittaria, p. 72.
white flowers in racemes; roots without
cross-constrictions (fig. 16).

<? H

Figure 15.

Figure 16.

23. Flowers with filaments connected by a funnel-like Hymenocallis, p. 109

membrane (crown) (fig. 17).
23. Flowers with free filaments (fig. 18) Crinum, p. 109.

FlGURE^lS.

44 PUBLIC HEALTH BULLETIN NO. 2 86

24. Stem usually triangular in cross-section Cyperaceae, p. 84.
particularly near base (edges sometimes
rounded) ; leaves 3-ranked, flowers in close
clusters and concealed by overlapping
scales.
24. Stems round in cross-section, leaves not 3- 25.
ranked.
25. Leaf with a ligule at base (junction of leaf and sheath) Graminae, p. 76.
(fig. 19).

25. Leaf without ligule 26,

26. Leaves with sheaths at base 27.

26. Leaves without definite sheaths, but bases 29.
sometimes sheathing.

27. Leaves narrow, mostly less than 1 cm. (fig. 20) Juncus, p. 107.

27. Leaves broader 28.

Figure 19.

Figure 20.

28. Sheaths abruptly contracted to blade of leaf ; Typha, p. 68.

leaves without keels (fig. 21).
28. Sheaths narrowed to blade; leaves with keels Sparganium, p. 68.

(fig. 22).

x'/6

x'/3

U ^'/e

Figure 21.

Figure 22.

A GUIDE AND KEY TO AQUATIC PLANTS

45

29. Leaves round 30.

29. Leaves flat .-- 32.

30. Flowers few, showy, pinkish purple (fig. 23).. Coreopsis, p. 140.

30. Flowers many in compound umbels, ineon- 31.
spicuous.

31. Fruit flattened laterally; fruit not winged (fig. 24) Ptilimnium, p. 131,

31. Fruit flattened dorsally; fruit prominently winged Oxypolis, p. 131.
(fig. 25).

• XIO

Figure 23.

Figure 25.

46 PUBLIC HEAl/TH BULLETIN NO. 286

32. Leaves keeled (fig, 10).- Acorus, p. 104.

32. Leaves not keeled 33.

33. Root red (fig. 26) Gyrotheca, p. 111.

33. Root not red 34.

34. Leaves equitant at base; flowers few and Iris, p. 110.
showy purple or sometimes white (fig. 13).

34. Leaves not equitant at base of plant 35.

35. Flowers white in dense button-like heads; leaves Eryngium, p. 130.

bristly-margined (fig. 27).

35. Flowers yellow, not in button-like heads nor with Polygala, p. 120.
bristly-margined leaves (fig. 28) .

Figure 26.

Figure 27.

Figure 28.

A GUIDE AND KEY TO AQUATIC PLANTS

47

KEY TO GROUP F
1. Leaves simple 2.

1. Leaves, or some of them, compound or at least cut 4.
into narrow segments almost to the midrib.

2. Leaves deeply lobed other than at base of 16.

blade.
2, Leaves not deeply lobed except sometimes at 3.
base of blade.
3. Leaves definitely lobed at base of blade; that is, lobes 20.
extending below the junction of the petiole and the
leaf.
3. Leaves not lobed but sometimes sessile and clasping 30.
at the base.

4. Leaves fern-like; plant not bearing flowers 5.

4. Leaves not fern-like; plants bearing flowers.- 6.
5. Spores borne in sacs on lower leaf surface; divisions of Anchistea, p. 67.

the leaf small, less than 2 cm. long (fig. 1) .
5. Spores borne on terminal modified leaves; divisions of Osmunda, p. 67.
the leaf larger, more than 2 cm. long (fig. 2) .

FiQUKE 1. Figure 2.

6. Leaves opposite (fig. 3) Bidens, p. 140.

6. Leaves alternate or irregularly placed 7.

7. Leaflets usually 3, no more than 5 (fig. 4) Ranunculus, p. 118.

7. Leaflets more than 5 8.

48 PUBLIC HEALTH BULLETIN NO. 286

8. Leaves with terminal leaflet largest 9.

8. Leaflets all near the same size 10.

9. Flowers yellow (fig. 5) Rorippa, p. 1 19.

9. Flowers white (fig. 6) _. Nasturtium, p. 119.

Figure 5.

Figure 6.

10. Plants with simple as well as compound 11,
1^ leaves.

10. Plants with all leaves compound 12,

11. Individual leaflets of compound leaves also lobed or Neobeckia. p. 119.

divided (fig. 7).
11. Individual leaflets simple (fig. 8) Proserpinaca, p. 129.

Figure 7.

A GUIDE AND KEY TO AQUATIC PLANTS

49

12. Base of petiole of leaf expanded into a sheath 13.
which encircles stem at junction.

12. Base of petiole not expanded (fig. 8) Proserpinaca, p. 129.

13. Leaves, at least the upper ones, only once compound Sium, p. 131.

(fig. 9)
13. Leaves twice divided 14.

14. Leaflets narrowly linear, untoothed; plants Ptilimnium, p. 131.

annual (fig. 10).
14. Leaflets wider, toothed; plants perennial (fig. Cicuta, p. 131.

11).

Figure 9.

FlGDBB 10,

Figure 11,

50

PUBLIC HEALTH BULLETIN NO. 286

15. Leaves coming off of a creeping or horizontal stem Hydrocotyle, p. 130.
(fig. 12).

15. Leaves scattered along an upright stem 16.

16. Leaves opposite 17.

16. Leaves alternate or irregularly borne 18.

17. Stems 4-angled; flowers small, in dense clusters in the Lycopus, p. 135.

axils of the leaves (fig. 13).

17. Stem round, or nearly so, in cross-section; flowers Bidens, p. 140.

showy, yellow (fig. 14).

x'/2
Figure 12.

^U

Figure 13.

Figure 14.

18. Leaves with veins radiating out from base 19.

of leaf.
18. Leaves with central mid-vein and smaller Rorippa, p. 119.
veins branching from this (fig. 15).
19. Base of petiole expanded; plants under 4 dm. tall (fig. Ranunculus, p. 118.

16).
19. Base of petiole not expanded; plants large, 5 dm. tall Hibiscus, p. 122.
or taller (fig. 17).

FiGUBE 15,

Figure 16.

Figure 17.

A GUIDE AND KEY TO AQUATIC PLANTS

51

20. Leaves all basal or arising from points along 21.
a horizontal stem.

20. Leaves distributed along stem 26.

21. Leaves coming off at points along a horizontal stem. 24.

21. Leaves basal to flower stalk 22.

22. Leaves with several prominent rib-like veins Alismaceae, p. 72.
running from base to apex (fig. 18).

22. Veins of leaves not prominent 23.

23. Leaves with blunt lobes; flower conspicuous, purple, Pontederia, p. 107.
not on a fleshy axis enclosed in a leaf-like sheath

(fig. 19).
23. Leaves usually with sharp lobes; flowers individually Peltandra, p. 103.
inconspicuous, on a fleshy axis enclosed in a leaf-
like sheath (fig. 20).

Figure 18.

Figure 19.

Figure 20.

24. Leaves small (less than 0.5 dm. long), coming 25.

off from slender, prostrate stems.
24. Leaves large (2 dm. long or more), coming Nuphar, p. 116,
off of stout underground stems (fig. 21).

25. Leaves toothed; veins of leaf irregular (fig. 22) Centella, p. 131.

25. Leaves entire; veins of leaf nearly parallel (fig. 23). __ Heteranthera, p. 106.

Figure 21.

Figure 22.

Figure 23.

52

PUBLIC HEAUTH BULLETIN NO. 286

26. Leaves toothed _ 27.

26. Leaves not toothed (entire) 28.

27. Plant small, less than 4 dm. tall; flowers yellow (fig. 24). Caltha, p. 118.
27. Plant large, over 5 dm. tall; flowers large, white, Hibiscus, p. 122.
pink, or purplish (fig, 25).

xyj

Figure 24.

Figure 25.

28. Leaves mostly basal, heart-shaped; flowers Pontederia, p. 107.

purple (fig. 26).
28. Leaves well distributed along stem; flowers 29.
not purple.
29. Sheaths (ocreae) around stem above each point of Polygonum, p. 1 14.
leaf -attachment; flowers white to red, not fragrant
(fig. 27).
29. Stems with no sheaths; flowers white, fragrant (fig. 28) _ Saururus, p. 112.

Figure 26.

Figure 27.

Figure 28.

A GUroE AND KEY TO AQUATIC PLANTS

53

30. Leaves all from one point, or mostly all basal, 33.
or from points along a horizontal stem.

30. Leaves distributed along the upright stem 31.

31. Leaves opposite.. 32.

3 1 . Leaves alternate or irregularly borne 40.

32. Leaves entire or nearly so 41.

32. Leaves prominently toothed 55.

33. Leaves from points along a horizontal stem, peltate. _ 34.

33. Leaves mostly basal, not peltate 35.

34. Leaves large, 2 dm. or more in diameter, Nelumbo, p. 117.
impossible to wet; flowers solitary, showy,
yellow (fig. 29).
34. Leaves small, only a few cm. across; flowers Hydrocotyle, p. 130.
small, white, and in close clusters (fig. 30).

Figure 29.

35. Leaves with several veins running from base to tip 36.

35. Veins not as above (fig. 31) Rumex, p. 113.

36. Leaves with several very prominent ribs Alismaceae, p. 72.
running from base to apex (fig. 32).

36. Leaves without prominent ribs 37.

Figure 31.

54

PUBLIC HEALTH BULLETIN NO. 286

37. Plants white-powdery above; plants extremely large, Thalia, p. 111.

usually over 1 m. (fig. 33).
37. Plants smaller; not white-powdery above 38.

38. Petiole often very short; leaves shed water Orontium, p. 102.

easily; flowers along fleshy spike enclosed

in a leafy sheath (fig. 34).
38. Petioles long; flowers and leaves not as above. 39.

39. Flowers many; leaves large, over 10 cm. long (fig. 35). Pontederia, p. 107.
39. Flowers solitary; leaves small, less than 5 cm. long Heteranthera, p. 106.
(fig. 36).

x'/6

Figure 35.

Figure 36.

A GUIDE AND KEY TO AQUATIC PLANTS 55

40. Leaves entire or nearly SO-.:. 65,

40. Leaves prominently toothed 77.

41. Leaf, when examined against light with lens, show- Hypericum, p. 123.
ing semitransparent dots; flowers yellow or pink

(fig. 37).

41. Leaves not showing semitransparent dots 42.

42. Leaves broadened at base 43.

42. Leaves narrowed to base 46.

43, Leaves mostly under 2.5 cm. long 44.

43. Leaves mostly over 2.5 cm. long 45.

44. Plant aromatic when crushed (fig. 38) Hydrotrida, p. 135.

44. Plant not aromatic when crushed (fig. 39) Herpestris, p. 135.

FlQURE 37.

Figure 38.

Figure 39.

56

PUBLIC HEALTH BULLETIN NO. 286

45. Flowers showy, in clusters, yellow or pink (fig. 37) Hypericum, p. 123.

45. Flowers not showy, in axils of leaves, mostly purple Ammannia, p. 125.
(fig. 40).
46. Leaves coverd with tiny black dots visible Gratiola, p. 135.

with lens; flowers small, white (fig. 41).
46. Leaves not covered with black dots; flowers 47.
various.

Figure 41.

47. Flowers conspicuous, at least 1 cm. long or across 48.

47, Flowers inconspicuous, small, less than 1 cm. long or 53.
across.

48. Flowers irregular, purplish (fig. 42) Justicia, p. 136.

48. Flowers regular 49.

49. Flowers yellow (fig. 37) Hypericum, p. 123.

49. Flowers not yellow 50.

50. Stem woody at least at base, arching; flowers Decodon, p. 125.

purple-pink, in auxiliary clusters (fig. 43).

50. Stems not woody and arching, but sometimes 51.
corky at base.

Figure 42.

Figure 43.

A GUIDE AND KEY TO AQUATIC PLANTS

57

51. Flowers purple; plant usually corky at base (fig. 44). _ Lythrum, p. 126.
51. Flowers white or pink; plant usually not corky at base. 52.

52. Flowers pink (fig. 37) Hypericum, p. 123.

52. Flowers white, or, if pink, with a yellow or Sabatia, p. 133.
green eye in center (fig. 45).

Figure 44.

Figure 45.

53. Flowers solitary in the leaf axUs 54.

53. Flowers in terminal clusters (fig. 46) Cynoctonum, p. 133.

54. Flowers with small appendages between the Rotala, p. 125.

sepals (fig. 47).

54. Flowers without small appendages between Didiplis, p. 125.

the sepals (fig. 48).

Figure 47.

xy4

Figure 48.

58

PUBLIC HEAI/TH BULLETIN NO. 2 86

55. Leaves with three prominent ribs — i 62.

55. Leaves without three prominent ribs 56.

56. Stems square or 4-angled 57.

56. Stems round in cross-section - 60.

57. Leaves petioled 58.

57. Leaves sessile 59.

58. Calyx of flower bearing a crest above (fig. 49) . Scutellaria, p. 135.

58. Calyx bearing no crest (fig. 50) Mimulus, p. 136.

Figure 49.

U X 73
Figure 50.

59. Flowers small, white, gathered in dense, sessile clusters
in the axils of the leaves (fig. 51).

59. Flowers solitary in the axils of the leaves (fig. 50)

60. Leaves small, mostly under 3 cm. long;
usually with black dots visible with a lens
covering them (fig. 52).
60. Leaves large, mostly over 5 cm. long and not
covered with black dots.

Lycopus, p. 135.

Mimulus, p. 136.
Gratiola, p. 135.

61.

Figure 51.

A GUIDE AND KEY TO AQUATIC PLANTS

59

61. Plants decumbent at base and usually rooting at the Lippia, p. 134.

lower nodes (fig. 53).
61. Plants entirely erect 63.

62. Leaves long petioled; flowers inconspicuous Boehmeria, p. 113.

(fig. 54).
62. Leaves sessile or very short petioled; flowers Rhexia, p. 124.

showy (fig. 55).

FiGURK 54.

Figure 55.

60

PUBLIC HEALTH BULLETIN NO. 286

63. Leaves long petioled; flowers minute, in sessile clusters Boehmeria, p. 113.
on branch (fig. 54).

63. Leaves sessile or short petioled 64.

64. Flowers showy, yellow, or at least with yellow Bidens, p. 140.

centers (fig. 56).
64. Flowers white or purplish (fig. 57) Eupatorium, p. 139.

Figure 56.

FlGUBE 57.

65. Leaves with several veins running from base to apex. _ 66.

65. Leaves with branched veins 67.

66. Leaves large, mostly over 6 cm. wide; flowers Canna, p. 111.

yellow, very large (fig. 58).

66. Leaves smaller; flowers individually small, in Habenaria. p. 1 12.
terminal spike-like clusters (fig. 59).

Figure 58.

A GUIDE AND KEY TO AQUATIC PLANTS

61

67, Stems with sheaths (ocreae) just above attachment 68.

point of leaves.
67. Stems without sheaths 69.

68. Plant with broad leaves, many basal; flowers Rumex, p. 113.

stalked and drooping (fig. 60) .
.68. Plant with narrower leaves, none basal; flow- Polygonum, p. 114.

ers sessile, in terminal spikes (fig. 61).

Figure 60.

FlUGRE 61.

62

PUBLIC HEALTH BULLETIN NO. 2 86

69. Leaves not over twice as long as broad (fig. 62) Samolus, p, 132.

69. Leaves much longer than broad 70.

70. Large herb with a very stout stem, often from Acnida, p. 115.

1 to 3 dm. in diameter at base, over 1.5 m.

tall (fig. 63).
70. Smaller herbs; ba.«e of stem sometimes corky 71.

but not extremely thick.

xya

Figure 62.

FlQUBE 63.

A GUIDE AND KEY TO AQUATIC PLANTS

63

71. Flowers blue, violet, or purple 72.

71. Flowers various but not blue or violet; petals some- 74.
times wanting.

72. Sepals united at base into a tube enclosing 73.
the ovary and later the fruit; leaves with-
out spines in axils.
72. Sepals free to base and not including the Hydrolea, p. 134.
ovary; leaves, or some of them, often with
spines in axils (fig. 64).

73. Sepals longer than the calyx tube, reflexed (fig. 65) Campanula, p. 138.

73. Sepals much shorter than the calyx tube, not reflexed Lythrum, p. 126.
(fig. 44).

Figure 64.

74, Flowers regular; petals, if present, yellow 75.

74. Flowers irregular; white, orange, or yellow 76.
in color.
75. Capsule or calyx tube short and stout, less than 1.5 cm. Ludwigia, p. 126.

long; stamens 4 (fig. 66) .
75. Capsule or calyx tube long and slender, over 1.5 cm. Jussiaea, p. 128.
long; stamens 8 (fig. 67).

Figure 66.

Figure 67.

64

PUBLIC HEAUTH BULLETIN NO. 286

76. Flowers in terminal clusters which may be Polygala, p. 120.

compound (fig. 68).
76. Flowers solitary or a few in the axils of the Hygrophila, p. 136.

leaves (fig. 69) .

xy3

FiGUKE 69.

77. Leaves aromatic when crushed (fig. 70) Pluchea, p. 139.

77. Leaves not aromatic 78.

78. Leaves large, over 5 cm. broad; flowers large, Hibiscus, p. 122.

over 5 cm. across (fig. 71).

78. Leaves and flowers much smaller 79.

Figure 70.

Figure 71.

A GUIDE AND KEY TO AQUATIC PLANTS

65

79. Flowers not in terminal clusters, but more or less dis- 81.

tributed over plant.
79. Flowers in terminal clusters 80.

80. Flowers conspicuous, white, 4-petaled; fruit as Neobeckia, p. 119.

in figure (fig. 72) .
80. Flowers greenish, 5-petaled; fruit as in figure Penthorum, p. 119.

(fig. 73).

Figure 72.

Figure 73.

81. Flowers sessile, in the axils of the leaves; fruit a single Proserpinaca, p. 129.

3-angled nutlet (fig. 74) .
81. Flowers stalked; fruit a group of several, scarcely Ranunculus, p. 118.

angled, small nutlets (fig. 75) .

^^

^

..^^^

Figure 74.

Figure 75.

INTRODUCTION TO THE CATALOG

On the following pages is a list of the families, genera, and species
of Southeastern aquatic plants. These follow the order of Robinson
and Fernald's seventh edition of Gray's New Manual of Botany, If
more than one species of a genus is present in the region, a key to the
species follows the generic name. In the case of the Gramineae, the
Cyperaceae, and the Alismaceae, illustrated keys within the family
are included, as these groups are in most cases not carried to the genus
in the main key.

The species list is annotated as to the range and habitat of the plants.
Range is given not only as to political units but also is stated in terms
of the physiographic regions involved. These physiographic regions
are delimited on the frontispiece map and a few remarks on them
follow. For economy of space statements of range, habitat, and fre-
quency are usually given in phrases rather than complete sentences.

The Coastal Plain, which is a region made up of recent sediments
lying adjacent to and extending back from our coasts, is the most
important from a malariological point of view. The length of this
guide is due in part to its rich aquatic flora, which is often quite
different from that of the more northern regions such as are so well
treated by Fassett in A Manual of Aquatic Plants. The subdivided
Mississippi Valley is geologically similar to the Coastal Plain but is
here differentiated because it has a distinctive flora.

The Piedmont, which consists of crystalline rocks or soils derived
therefrom, has few extensive aquatic areas and is thus of less im-
portance from the point of view of mosquito breeding. The Blue
Ridge is also of little interest, and aquatic plants found in our terri-
tory only in the mountams are not considered in this guide. The
paleozoic Appalachian Provinces and the Interior Low Plateaus do
have a problem, along their larger rivers, especially in the vicinity of
impoundments.

Also annotated are synonyms when nomenclature in this treatment
differs from that offered by Small, Manual of the Southeastern Flora.
A few notes on the association of mosquitoes with specific plants are
given, but sufficient knowledge is lacking to make extensive general-
izations.

A recently introduced species, the water-chestnut (Trapa natans L.),
has not been recorded from our territory but occurs nearby in the
Potomac River, where it has been found harboring Anopheles quad-
rimaculatus. It is not listed in this catalog.
66

CATALOG OF AQUATIC PLANTS

THALLOPHYTA

CHARACEAE Muskgrass family

1. Chara L.

Chara spp. — No attempt will be made to differentiate here the
species of Chara, nor will it be attempted to distinguish Chara from
the related Nitella (not listed). This list was designed to include
primarily the vascular aquatic plants, and Chara is included because
it has characters which make it simulate vascular species and because
Anopheles qvudrimaculatus is sometimes found associated with it.

BRYOPHYTA

RICCIACEAE Thallose liverworts

1. Riccia L.

. R. jluitans L. — Ponds, swamps and springs over all our territory.

2. Ricciocarpus Corda

i?. natans (L.) Corda— Common in ponds and swamps over most of
our territory.

PTERIDOPHYTA

OSMUNDACEAE Flowering fern family

1. Osmunda L.

0. regalis L. var. tipectabilis (Willd.) A.Gray. Royal-fern — When
aquatic mostly in alluvial swamps, not commonly encountered, range
includes all of our territory.

POLYPODIACEAE Fern family
1. Anchistea Presi

A. virginica (L.) Presl. Virginia Chain-fem — Ranges over all of
our Coastal Plain, most often found in very acid swamps or ponds.

SALVINIACEAE Salvinia family

1. AzoIIa Lam.

A. caroliniana Willd. Mosquito Fern — Assumes a red color when
growing in the sun. Common in ponds, lakes and alluvial swamps
over most of our area.

67

68 PUBLIC HEALTH BULLETIN NO. 2 86

ISOETACEAE Quillwort family
1. Isoetes L.

/. Jlaccida Shuttlw. Quillwort — Limesink ponds and other situa-
tions, Coastal Plain, South Georgia, and Florida. There are two
varieties distinguishable in fruiting condition. There are several
additional species of this genus in our territory, but only the above
is likely to be encountered in mosquito work.

GYMNOSPERMAE

PINACEAE Pine famUy

1. Pinus [Tourn.] L.

P. serotina Michx. Pond-pine — Acid ponds and swamps, Coastal
Plain, Florida north to beyond the limits of our territory and west at
least to Alabama.

2. Taxodium L. C. Rich.

T. distichum (L). L. C. Rich. Cypress — This species, with two-
ranked spreading needles, has a well-marked Coastal Plain variety
with appressed needles (variety imbricarium (Nutt.) Sudw.) The
variety with appressed needles is particularly characteristic of acid
ponds in the Coastal Plain, whUe the typical plant is found over all
our area (except the Piedmont and mountains) and reaches its best
development in river swamps.

ANGIOSPERMAE

TYPHACEAE Cattail famUy

1. Typha [Tourn.] L.

1. Leaves flat; inflorescence with staminate and dark 1. T. latifolia.
brown pistillate portions separated; pollen of simple
grains.

1. Leaves rounded on back; inflorescence with staminate 2. T. anguslifoUa.
and light brown pistillate portions usually contig-
uous; pollen grains grouped in 4'8.

.1. T. latifolia L. Broad-leafed Cattail — Common over all our terri-
tory. Anopheles quadrimaculatus often found associated.

2. T. angustifolia L. Narrow-leafed Cattail — Characteristic of
aquatic situations along the coast, very local inland, much less com-
mon than the preceding.

SPARGANIACEAE Bur-reed family

1. Sparganium [Tourn.] L.

L Achene fusiform, the body stalked; stigma 1 1. S. americanum.

I. Achene obpyramidal, cut nearly square across top; 2. S. eurycarpum.
stigmas 2

A GUIDE AND KEY TO AQUATIC PLANTS

69

1. S. eurycarpum Engelm, Bur-reed — Not common in the south-
east, but noted north of our territory in association with Anopheles
quadrimaculatus .

2. S. americanum Nutt. Bur-reed — Not collected by the writers
but supposed to occur over most of our territory.

NAJADACEAE Pondweed Family

1. Potamogeton [Tourn.] L.

I. Plants with both floating and submerged leaves, the 2.
floating leaves with expanded blades and differing
from submerged ones.

1. Plants with all leaves alike and submerged 10.

2. Submerged leaves filiform or very narrowly 3.

linear, less than 2 mm. wide.
2. Submerged leaves lanceolate or ovate or if 5.
linear more than 2 mm. wide.

3. Flowers in cylindrical, many-flowered spikes only 1. P. nutans.

3. Flowers in globular, few-flowered spikes in the axils of 4.
the submerged leaves as well as in cylindrical,
many-flowered emersed spikes.

4. Submerged leaves 0.5-2 mm. wide, not taper- 2. P. diver sijoliua.
ing to a long point; floating leaves, when
present, rounded at the tip, the larger 5-15
nerved.
4. Submerged leaves 0.1-0.6 mm. wide, taper- 3. P. capillaceus.
ing to a long point; floating leaves, when
present pointed at the tip, 3-7 nerved

5. Submerged leaves linear and ribbon-like 4. P. epihydrus.

5. Submerged leaves lanceolate or ovate 6.

6. Floating leaves heart-shaped at base 5. P. pulcher.

6. Floating leaves rounded or tapering at base. 7.

7. Floating leaves with 30-50 nerves 6. P. amplifoUus.

7. Floating leaves with less than 30 nerves 8.

8. Upper submerged leaves with long petioles. _ 7. P. nodosus.
8. Upper submerged leaves with obscure short 9.
petioles or sessile.
9. Submerged leaves with an abrupt awl-shaped tip, 2-4 8. P. angustifoUua
mm. long.

9. Submerged leaves with no awl-shaped tip. 9. P. gramineus.

10. Leaves lanceolate or broader, with curved 11.

not parallel sides.
10. Leaves thread-like or ribbon-like, linear 15.
with parallel sides.
11. Leaves short petioled or sessile but not clasping at 12.
base.

11. Leaves clasping at base 14.

12. Leaves with an awl-shaped tip 2-4 mm. long 13.

12. Leaves without awl-shaped tip 9. P. gramineus.

13. Fruit with a single keel 10. P. illinoensis.

13. Fruit with 3 distinct keels 8. P. angustifolius.

70 PUBLIC HEALTH BULLETIN NO. 286

14. Leaves undulate or crisped with 3-7 promi- 11. P.perfoliatus.
nent nerves.

14. Leaves flat and with 1 prominent nerve 12. P. bupleuroides.

15. Leaves ribbon-like, more than 2 mm. wide 4. P. epihydrus.

1 5. Leaves narrower, usually filiform 16.

16. Stipules united to base of leaf forming a 13. P. pectinatus
sheath more than 1 cm. long; fruits on
spike interrupted appearing like beads on
a string.
16. Stipules not united to leaves or if united 17.
forming a sheath much less than 1 cm.;
fruits continuous on spike.
17. Plants with axillary globular spikes as well as cylindric 18.
terminal spikes; fruit flat and spiralled like a snail
shell.
17. Plants with terminal cylindric spikes only; fruit plump. 19.

18. Submerged leaves 0.5-2 mm. wide, not taper- 2. P. diversifolius.
ing to a long point; floating leaves, when
present, rounded at the tip, the larger 5-15
nerved.
18. Submerged leaves 0.1-0.6 mm. wide, tapering 3. P. capilloceus.
to a long point; floating leaves, when
present, pointed at the tip, 3-7 nerved.

19. Leaves without basal glands 14. P. foliosus.

19. Leaves with a pair of glands at base of leaf 15. P. berchtoldi.

1. P. natans L. — Found in various provinces but known only from
northern part of our territory in Tennessee.

2. P. diversifolius Raf. Pondweed.— One of our more common
Pondweeds, found in various provinces over most of our territory,
although no positive record from Florida. Anopheles quadrimaculatus
sometimes found associated.

3. P. capillaceus Poir.^-Very similar to preceding but more char-
acteristically Coastal Plain in distribution, found in all of our States
except Tennessee. In Tennessee there are a few stations for the very
similar P. hicujtulatus Fernald which may be distinguished by its light
brownish fruits with a coarsely toothed keel from P. capillaceus with
its greenish fruit with an entire or finely toothed keel. P. capillaceus
is often found in rather acid waters.

4. P. epihydrus Raf.^ — ^Known in our territory only from highland
areas in Georgia, North Carolina, and Tennessee.

5. P. pulcher Tuckerm. — Found in ponds in various provinces,
range includes all of our territory, not frequent.

6. P. amplifolius Tuckerm. — Range similar to preceding, found
mostly in hard waters.

7. P. nodosus Poir. — One of the more common Pondweeds, found
in various provinces, range includes all of our territory, commonly
referred to as Potamogeton americanus C. & S.

A GUIDE AND KEY TO AQUATIC PLANTS 71

8. P. angustifolius Berchtold & Presi — Range same as two preced-
ing, but infrequent.

9. P. gramineus L. — The range of this very variable species covers
all of our territory.

10. P. illinoensis Morong — Should occur over all of our range.

11. P. perfoliatus L. — Slow streams and ponds, various provinces,
over all of our territory.

12. P. bupleuroides Fernald— Found mostly in brackish waters,
range extends south to Florida.

13. P. jpectinatus L. — Characteristic of hard water streams or lakes,
range includes all of our territory.

14. P. foliosus Raf. — Known from our area only in Georgia and
Tennessee except fpr isolated stations in the Coastal Plain of South
Carolina and Florida.

15. P. berchtoldi Fieber — Very variable species, known only from
one or two isolated stations in our territory, probably occurs more
widely unrecognized. Cited as P. pusillus L. by Small.

2. Zannichellia [Mich.] L.

Zannichellia palustris L. Horned Pondweed — Hard waters and
brackish as well as fresh situations, infrequent, should range over most
of our area.

3. Najas L.

1. Seed shining and obscurely marked; style 1 mm. or

more long. l.A'^. flexilis.

1. Seed dull, coarsely pitted; style 0.5 mm. long or less 2. N. guadalupensis.

1. A^. flexilis (Willd.) R. & S. — Species of Najas observed by the
senior author in the southeast have not been separated, but this is
likely the most common species.

2. A^. guadalupensis (Spreng.) Morong — Supposed to be rare and
local. In addition another species, A^^. gracilis (Morong) Small, listed
by Small from fresh water situations in Florida, is probably more
properly A^. marina L. var. gracilis Morong.

4. Ruppia L.

R. maritima L. Widgeon-grass — Rarely occurs inland, primarily a
brackish water species, noted in artesian porids along the coast in
Georgia.

72

PUBLIC HEALTH BULLETIN NO. 2 86

ALISMACEAE Water plantain family

1. Fruits borne in a ring; stamens 6; inflorescences much 1. Alisma, p. 72.

branched (fig. 1).
1. Fruits in dense heads; stamens usually more than 6; 2.
Infloi scences not greatly branched.

2. Lowest flowers with only carpels, or with only 2. Sagittaria, p. 72.

stamens (fig. 2).
2. Lowest flowers with both stamens and carpels — 3.

Figure 1.

Figure 2.

3. All flowers with stamens and carpels (fig. 3) .
3. Upper flowers with stamens only (fig. 4)

3. Echinodorus, p. 75.

4. Lophotocarpus,p.75.

Figure 3.

Figure 4.

1. Alisma L.

A. subcordatum Raf. — Should occur over most of our territory but
noted only a few times. Seems to prefer alluvial situations,

2. Sagittaria L.

1. Sepals appressed to the fruit head 1. S. montevidensis.

1. Sepals lax or reflexed but not appressed to the fruit 2.
head.

2. Fruit-bearing pedicels reflexed or recurved 3.

2. Fruit-bearing pedicels ascending. _. 5.

A GUIDE AND KEY TO AQUATIC PLANTS 73

3. Filaments glabrous 4.

3. Filaments pubescent 2. S. platyphylla.

4. Inflorescence not branched; leaves not atten- 3. S. subulata.
uate.

4. Inflorescence branched; leaves attenuate 4. S. filtformis.

5. Leaves without basal lobes 6.

5. Leaves, at least some of them, with basal lobes 16.

6. Pedicels of pistillate flowers as long (or nearly 7.

so) as staminate.
6. Pedicels of pistillate flowers very short or 15.
nearly wanting.

7. Filaments not dilated, slender 8.

7. Filaments dilated, relatively short 10.

8. Bracts and sepals granular-papillose 5. S. falcata.

8. Bracts and §epals ribbed. __ 9.

9. Acbene gradually long-beaked; dorsal wing thick and 6. S. lancifolia.

even.
9. Achene abruptly minutely beaked, dorsal wing thick 7, S. angustifolia.
and crested.

10. Leaf-blades 3-sided, often imperfectly devel- 11.
oped.

10. Leaf-blades flat 12.

11. Achene 2 mm. long with several facial wings; anthers 8. S. teres.

longer than filaments.
11. Achene 1 mm. long with 3 low facial ribs; anthers 9. S. isoetiformis.
shorter than filaments.

12. Achene oval or broadly elliptic 10. S. cycloptera.

12. Achene cuneate 13.

13. Beak large, horizontal, at top of achene body 11. <S. mohrii.

13. Beak minute, borne below top of achene body 14.

14. Inflorescence simple; achene with lateral 12. S. graminea.

wings or ribs.
14. Inflorescence compound; achene without 13. S. chapmanii.
lateral ribs or wings.
15. Fruit head not echinate; achene widely-winged and 14. S. macrocarpa.

short-beaked.
15. Fruit head echinate; achene narrowly-winged and 15. S. rigida.
long-beaked.

16. Achene minutely beaked . 12. S. graminea.

16. Achene prominently beaked 17.

17. Beak of achene horizontal or nearly so 16. S. latifolia.

17. Beak of achene erect 18.

18. Filaments pubescent 19.

18. Filaments glabrous. 17. S. longirostr a.

19. Pistillate pedicels very short; sepals and bracts glab- 15. S. rigida.

rous.
19. Pistillate pedicels elongate; sepals and bracts pubes- 18. S. viscosa.
cent,

1. S. montevidensis C. &. S. Giant Arrow-leaf — Noted by the senior
author only in ditches, marshes, and ponds along the coast but
probably occurs elsewhere. Is easily distinguished by its gigantic
size — the leaves sometimes reach a half a meter in length.

74 PUBLIC HEALTH BULLETIN NO. 286

2. S. platyphylla (Engelin.) J. G. Smith. Swamp-potato — Found
only in the western part of our territory, most abundant along the
lower Mississippi River.

3. S. subulata (L.) Buchenau — The representative of this species
most likely to be found in southeastern fiesh water habitats is var.
natans J. G. Smith. Has not been collected by the writers.

4. S. Jiliformis J. G. Smith — Ponds in Alabama, Florida, and
possibly the Carolinas. It has not been noted by the writers.

5. S.Jalcata Pursh — Similar to the following two species. Collected
from ponds and marshes along the Georgia coast.

6. S. lancifolia L. — The giant Sagittaria of the Everglades, often
grows higher than a man's head. Should be found only in the southern
part of our territory.

7. S. angustifolia Lindl. — Georgia to Louisiana in swamps, not
noted by the writeis.

8. S. teres S. Wats. — This small Sagittaria with imperfectly de-
veloped leaves has been collected by the senior author from the edges
of open, acid limesinks in southwest Georgia. Its published range is
South Carolina to Massachusetts,

9. S. isoetijormis J. G. Smith — Said to occur in Georgia and Florida
in the Coastal Plain.

10. S. cycloptera (J. G. Smith) C. Mohr — Swamps in the Coastal
Plain, Florida to South Carolina and westward along the Gulf of
Mexico to beyond the limits of our range.

11. S. mohrii J. G. Smith^Coastal Plain, Florida to Georgia and
Mississippi in ponds.

12. S. graminea Michx.— This narrow-leafed Sagittaria should range
over most of our territory. 'Has been noted often.

13. S. chapmanii (J. G. Smith) C. Mohr — Strictly Coastal Plain
in distribution, Florida, Georgia, and Alabama.

14. S. macrocarpa J. G. Smith— Ponds, South and North Carolina

15. S. rigida Pursh— Well distributed species, probably not com
mon in our territory, although said to occur south to Florida. Forma
elliptica (Engelm.) Fernald has broad and sometimes lobed leaves.

16. S. latijolia Willd. — Most abundant and one of our most variable
species, found in some form over all of our territory. Variety puhes-
cens (Muhl.) J. G. Smith is hairy on the bracts, sepals, and inflores-
cence rachis and is primarily Coastal Plain in distribution. Variety
obtusa (Muhl.) Weigand has the leaf tap blunt or rounded. Forma
gracilis (Pursh) Robinson has very narrow leaf -lobes. Fornia diver-
sifolia (Engelm.) Robinson has lobeless as well as lobed leaves.
Forma hastata (Pursh) Robinson has hastate rather than sagittate
leaves. This species has been found in association with Anopheles
quadrimaculatus .

A GUIDE AND KEY TO AQUATIC PLANTS 75

17. S. longirostra (Micheli) J. G. Smith — Usually found in the
Coastal Plain, noted in acid, open ponds in Georgia.

18. S. mscosa C. Mohr — Restricted to North Florida and South
Alabama in marshes.

3. Echinodorus L. C. Rich.

1. Achene with little or no beak, stamens 9; plants small 1. E. tenellus.

(usually less than 1.5 dm.), leaves narrow.
1. Achene prominently beaked, stamens 12-21; plants 2.
usually longer, leaves broadened,

2. Flowering stems erect; stamens 12 2. E. cordifolia.

2. Flowering stems arching or creeping, often root- 3. E. radicans.
ing at nodes; stamens about 21.

1. E. tenellus (Martins) Buchenau — Should range over most of our
territory, not noted by the writers. Called by Small Helanthium
parvulum (Engclm.) Britton.

2. E. cordijolius (L.) Griseb. Burhead — Should also be well dis-
tributed over our area, not common.

3. E. radicans (Nutt.) Engelm. Burhead — Well distributed over
our area, but infrequent. Prefers hard or neutral waters, noted
principally in alluvial aquatic areas.

4. Lophotocarpus T. Durand

L. calycinus (Engelm.) J. G. Smith — Confined to western part of
our territory. Noted along Mississippi River just north of our
territory.

HYDROCHARITACEAE Frog-bit family

1. Anacharis Planch

1 . Leaves 3 in whorls; petals less than S mm. long or want- \. A. canadensis.

ing.
1. Leaves 4 in whorls; petals prominent, about 1 cm. long. 2. A. densa.

1. A. canadensis (Michx.) Planch. Waterweed — Occurs mostly
north of our territory but present in Reelfoot Lake, Tennessee.

2. A. densa (Planch.) Victorin — Occurs as an escape from aquaria.
Collected in Chatham County, Georgia, where it harbored Anopheles
quadrimaculatus . Besides the above two, there is a third, very local
species in middle Tennessee.

2. Vallisneria [Mich.] L.

V. americana Michx. Eelgrass — Some authorities differentiate two
species of Vallisneria in the southeast, but these two are very similar.
Except along the Gulf Coast, Eelgrass is very rare (or absent) in our
territory.

76

PUBLIC HEALTH BULLETIN NO. 2 86

3. Limnobium L. C. Rich.

L. spongia (Bosc) Steud. Frog-bit — Fairly common over most of
our territory. It has been noted in very acid and in alkaline waters,
thus showing considerable tolerance. It has been found in associa-
tion with Anopheles and is mat-forming.

GRAMINEAE Grass family

1. Plants floating, or forming mats at surface of water', 2.

or creeping along ground.
1, Plants essentially erect 3.

2. Leaves floating flat on surface; inflorescences 7. Hydrochloa, p. 82.

minute and inconspicuous (fig. 1).
2. Leaves not flat-floating; inflorescences large 9. Paspalum, p. 82.

and conspicuous (fig. 2) .

a/Z

FlOUBB 1.

Figure 2.

A GUIDE AND KEY TO AQUATIC PLANTS

77

3. Plants with two kinds of spikelets; that is, pistils and 4.

stamens borne in different spikelets.
3. Plants with all spikelets alike; stamens and pistils in 6.
same spikelets.

4. Inflorescences not expanded; the lower pistil- 16. Tripsacum,p. 84.
late portion breaking up into bony, bead-
like joints (fig. 3).

4. Inflorescence expanded 5.

5. Pistillate spikelets borne above staminate in inflores- 4. Zizania, p. 81.

cence; leaves not cutting (fig. 4).
5. PistuUate and staminate spikelets intermixed; leaves 6. Zizaniopsis, p. 82.
with scabrous, cutting margins (fig. 5).

Figure 3

x'A
Figure 4.

Figure 5,

78 PUBLIC HEALTH BULLETIN NO. 2 86

6. Plants woody, bamboo-like (fig. 6) 1. Arundinaria, p. 80.

6. Plants not woody 7.

7. Inflorescence made up of bony, bead-like joints 15. Manisuris, p. 84.
(fig. 7).

7. Inflorescence not made up of bony, bead-like joints 8.

8. Inflorescence feathery, long-hairy, or spiny 9.

8. Inflorescence smooth 11.

9. Inflorescence plume-like, feathery or at least spiny; 10.

not appearing branched.

9. Inflorescence not plume-like nor feathery; panicle 12. Echinochloa, p. 88.
obviously branched (fig. 8).

FlQtTRE 6.

Figure 7.

Figure 8.

A GUIDE AND KEY TO AQUATIC PLANTS

79

10. Spikelets spineless (awnless)' but subtended 13. Setaria, p. 84.

by several bristles; panicle often nodding

(fig. 9).
10. Spikelets long-spiny (long-awned), with or 14. Erianthus, p. 84.

without hairs at base; panicle not nodding

(fig. 10).

Figure 9.

FiGUEE 10.

11. Spikelets appressed along one side of rachis, forming 12.
1 to many compact 1 -sided spikes or spike-like
racemes.

1 1. Spikelets not appressed along one side of rachis 14.

12. Spikelets 6 mm. long or more; grass grow- 3. Spartina, p. 81.
ing in huge clumps (fig. 11).

12. Spikelets 5 mm. long or less 13.

13. Spikelets arranged along rachis with back of fruit 8. Axonopus, p. 82.

away from rachis; rachis 3-sided (fig. 12).
13. Spikelets arranged along rachis with back of fruit 9. Paspalum, p. 82.
toward rachis; rachis often winged or foliaceous
(fig. 2).

FlQUBB 11.

Figure 12.

80 PUBLIC HEALTH BULLETIN NO. 286

14. Spikelets with several florets (fig. 13) 2. GlyCeria, p. 81.

14. Spikelets 1-flowered 15.

15. Spikelets very strongly flattened (fig. 14) 4. Leersia, p. 81.

15. Spikelets not strongly flattened 16.

Figure 13.

Figure 14,

16. Spikelets inflated or gibbous at base (fig. 15) 11. Sacciolepis, p. 83.

16. Spikelets not inflated at base (fig. 16) 10. Panicum, p. 82.

XI

x\0

Figure 16.

1. Arundinaria Michx.

1. Panicles on leafy branches; stems often over 2 m. high. 1. A. gigantea.
1. Panicles on naked shoots from rhizomes; stems usually 2. A. tecta.
under 2 m. high.

1. A. gigantea (Walt.) Chapm. Giant Cane — Occurs in colonies or
canebreaks, mostly along river lowlands. Flowers very infrequently
and for that reason is sometimes difficult to distinguish from the
following species. Both species occur over all of our area, but the

A GUIDE AND KEY. TO AQUATIC PLANTS 81

Giant Cane is evidently much less abundant. Phragmites communis
Trin., another large bamboo-like species, is found locally in our terri-
tory, mostly in brackish situations. It may be distinguished by its
wide, spreading leaves and its feathery inflorescence.

2. A. iecta (Walt.) Muhl. Small Cane — More characteristically
Coastal Plain in distribution than the Giant Cane, very frequent in
moist places of many kinds but rarely present in any depth of water.

2. Glyceria R. Brown

G. sepientrionalis Hitchc. — Only representative of this primarily
aquatic genus which must be considered in our territory, not common.
It has been recorded from Alabama and South Carolina, and the
senior writer collected it on one occasion from a limesink in Coastal
Plain Georgia.

3. Spartina Schreb.

1. Spikes numerous, at least more than 10; inflorescence 1. S. spartinae.

dense, cylindric.
1. Spikes fewer, not more than 10; inflorescence not dense. 2. S. bakeri.

1. S. spariinae (Trin.) Merr. Cordgrass — Several species of this
genus occur in our territory but only this and the following species
are characteristically found in fresh water. In our territory it has
been collected near the coast in Florida and Mississippi where it
occurs in marshes and swamps.

2. S. bakeri Merr. Cordgrass — Well distributed in Florida, found
less commonly near the coast in Georgia and further north; occurs
also in brackish water.

4. Leersia Swartz

1. Spikelets broadly oval, 3 to 4 mm. wide 1. L. lenticularis.

1. Spikelets narrower, elliptic 2.

2. Panicles narrow the branches ascending or ap- 2. L. hexandra.

pressed.

2. Panicles expanded, the branches spreading 3. L. oryzoides.

1. L. lenticularis Michx. Catchfly-grass — Ranges over all our area,
found mostly along the larger rivers.

2. Z. hexandra. Swartz. Cutgrass — Found by the writers mostly
in acid situations, range includes all of our Coastal plain.

3. L. oryzoides (L.) Swartz. Rice Cutgrass — Most widespread and
abundant Leersia in our territory, frequently found in limesink ponds
in Georgia, may be found along rivers and probably elsewhere, range
includes all of our territory .

5. Zizania L.

Z. aquatica L. Wild rice — Not common in our territory, seen most
frequently in fresh-water marshes near the coast, but has been recorded
from every State in our range.

82 PUBLIC HEALTH BULLETIN NO. 2 86

6. Zizaniopsis Doell and Aschers

7j. miliacea (Michx.) Doell and Aschers. Cutgrass — Often giows
in the same situations as Zizania but usually more abundant. Marshes
along the larger rivers seem to be favored by it, and in Reelfoot Lake,
Tennessee, Anophelei^ qtiadrimactilahis has been found associated with
it. Its range includes all of our Coastal Plain.

7. Hydrochloa Beauv.

/-]. caroliniensis Beauv. — Widespread in the Coastal Plain, Florida
to North Carolina and Louisiana; occurs in acid to neutral water,
showing considerable tolerance; has often been found harboring
Anopheles quadrimaculatus .

8. Axonopus Beauv.

1. Spikelets 4 to 5 mm. long, glabrous I. A. furcatus.

1. Spikelets about 2 mm. long, sparsely appressed, silky — 2. A. affinis.

\. A. Jurcatus (Fliigge) Hitchc. — Coastal Plain species, noted
along acid lake margins in the Okefmokee Swamp, occurs in all of our
States except Tennessee.

2. A. affinis Chase. Carpet-grass — Coastal Plain species, most

often found in acid situations, well distributed over our area but

seldom grows in over an inch or two of water. Often behaves like a

weed.

9. Paspalum L.

1. Rachis of inflorescence foliaceous, broad 2.

1. Rachis not foliaceous or winged 3.

2. Rachis extending beyond uppermost spikelets; 1. P.repens.

racemes many, at least ovej" 6.
r, Racliis not extending beyond uppermost spike- 2. P. dissectmn.
let ; racemes 2 to 4.

3. Racemes usually 2 (sometimes with a third) 3. P. distichum

3. Racemes usually 4 to 6 4. P. praecox.

1. P. repens Berg. — Floating or reclining plant, has been recorded
from all the States in our territor}' except possibly North Carolina, not
frequent.

2. P.. dissectum L. — Well distributed in our area, infrequent, col-
lected once from limesink in Georgia, habit similar to preceding.

3. P. distichum L. — Has been recorded from all of the States in our
territory, most common near the coast.

4. P. praecox Walt. — Coastal Plain, sometimes in aquatic situa-
tions. In addition to the four species given above, there are several
other species of Paspalum which sometimes occur in wet places, but
since this is only an occasional habit for these species they are not

included here.

10. Panicum L.

1. Spikelets short-pedicelled along one side of the rachis 2.

forming spike-like racemes.
I. Inflorescences open or sometimes contracted and with 3.

one-sided racemes but not as above.

A GUIDE AND KEY TO AQUATIC PLANTS 83

2. Glume almost as long as the lemma 1. P. gymnocarpon.

2. Glume much shorter than lemma 2. P. hemitomum.

3. Plants with conspicuous creeping rhizomes 3. P. virgatum.

3. Plants without creeping rhizomes 4.

4. Panicles narrow and few-flowered 4. P. tenerum.

4. Panicles more or less spreading 5.

5. Spikelets 1.8 to 2 mm. long; panicle branches ascend- 5. P. agrostoides.

ing or spreading.

5. Spikelets 2.5 mm. long; panicle branches erect or 6. P. condensum.
nearly so.

1. F. gymnocarpon Ell. — Lower Gulf State species, Georgia and
Florida westward, usually associated with rivers or streams.

2. P. hemitomum Schultes. Maideucane — Coastal Plain species,
ranges over all of our Coastal Plain territory. Makes good growth
in open, grassy limesinks and occurs also in the Okefinokee Swamp.
It is perhaps the most important of the aquatic Panic-grasses.

3. P. virgatum L. Switchgrass — Aquatic and other situations
mostly along the coast, but range includes most of our atea.

4. P. tenerum Beyr. — Coastal Plain, North Carolina to Florida and
Texas, seems to prefer acid situations.

5. P. agrostoides Spreng. — ^Well distributed over our area, in some
places {\n important constituent of the aquatic flora, usually occupies
a marginal position.

6. P. condensum Nash — Resembles the preceding, but of Coastal
Plain distribution. In addition to the six given, there are several
other Panic-grasses which sometimes appear to be aquatic, and there
are in South Florida perhaps two truly aquatic species which are not

listed.

11. Sacciolepis Nash

S. striata (L.) Nash — Frequent in portions of our region, in Georgia
seems to prefer acid situations, range includes all of our Coastal

Plain.

12. Echinochloa Beauv.

I. Lower leaf-sheaths smooth; awns various but panicles 1. E. crusgalli.

not densely hairy.
I. Lower leaf-sheaths hairy; panicles densely hairy from 2. E. ivaUeri.

long-awned spikelets.

1. E. crusgalli (L.) Beauv. Wild Millet — Widely distributed, often
weedy, range includes all of our area, it and the following species
common near the coast.

2. E. walteti (Pursh) Heller — In marshes along the coast, less
commonly in aquatic areas near the larger rivers, range includes all
of our territory.

84

PUBLIC HEALTH BULLETIN NO. 2 86

13. Setaria Beauv.

S. magna Griseb. Giant Bristlegrass — Marshes near the coast over
most of our territory.

14. Erianthus Michx.

1. Spikelets naked or nearly so at base 1. E. strictus.

1. Spikelets with a conspicuous hair tuft at base 2.

2. Basal hairs sparse and shorter than spikelets 2. E. brevibarbis.

2. Basal hairs copious and longer than spikelet 3. E. giganteus.

1. E. siricius Baldw. Narrow Plumegrass — Coastal Plain acid
aquatic areas, over most of our area.

2. E. brevibarbis Michx. Brown Plumegrass — Distribution similar
to the preceding.

3. E. giganteus (Walt.) Muhl. Giant Plumegrass — More truly-
aquatic than the preceding two, similarly distributed.

15. Manisuris L.

M. rugosa (Nutt.) Kuntze — In acid situations, range includes all
of our Coastal Plain territory.

16. Tripsacum L.

T. daciyloides L. Gamagrass — Widely distiibuted in moist places;
not common, range includes all of our territory.

CYPERACEAE Sedge family

1 . Flowers with both stamens and pistils 2.

1. Stamens and pistils in different flt)wers 12.

2. Stem with one or more terminal spikelets; 3.

leaves absent. '
2. Stem with a leaf or leaves extending beyond 4.
spikelets (If a single leaf, this leaf may
appear like continuation of scape) .
3- Stem topped by a single spikelet; a leaf -sheath present 4.

only at the base of the stem (fig. 1).
3. Stem topped by 1 to several spikelets; leaf -sheaths dis- 6.
tributed along the stem (fig. 2).

Eleocharis, p. 88.
Fuirena, p. 93.

Xl •'!

Figure 1

FlOUBE 2

A GUIDE AND KEY TO AQUATIC PLANTS

85

4. Spikelets subtended by conspicuous white or 7. Dichromena, p. 94.
partly white bracts (fig. 3) .

4. Spikelets not subtended by white bracts 5.

5. Scales of the spikelet 2-ranked, often making the spike- 6.

let appear flattened.
5. Scales of the spikelet spirally overlapping, not 2-ranked- 7.

6. Stem round, hollow; spikelets borne in axil- 1. Dulichium, p. 87.

lary as well as terminal clusters (fig. 4).
6. Stem3-angled,sometimesbluntly so; spikelets 2. Cyperus, p. 87.
borne in terminal clusters (fig. 5).

Figure 3

Figure 4

Figure 5

86

PUBLIC HEALTH BULLETIN NO. 286

7. Achene bearing a tubercle (formed by the swollen per- 8.

sistent style base) .
7. Achene not bearing a tubercle 9.

8. Spikelets with more than 2 scales enclosing 8. Psilocarya, p. 94.

achenes; no perianth-bristles present (fig. 6) .
8. Spikelets with only 1 or 2 scales enclosing 9. Rhynchospora, p. 94.

achenes; perianth-bristles usually present

(fig. 7).

Figure 6

Figure 7

9. Spikelets with the uppermost scale only enclosing an 10. Cladium, p. 98.
achene; our commonest species has saw-edged, cut-
ting leaves (fig. 8).
9. Spikelets with the upper several scales bearing achenes ; 1 0.
leaves not armed.

10. Each scale of spikelet bearing a bristle or awn 6. Fuirena, p. 93.

near the apex (fig. 9).
10. Each scale of spikelet not bearing a bristle or 11.
awn.

Figure 8

Figure 9

A GUIDE AND KEY TO AQUATIC PLANTS

87

11. Style swollen at base but the swollen basse not persist- 3. Fimbristylis, p. 88.

ent on achene (fig. 10).
11. Style not swollen at base (tig. 11) 5. Scirpus, p. 91.

X 20

Figure 10

Figure 11

12. Achene exposed (fig. 12) 11. Scleria, p. 98.

12. Achene enclosed in a sac (perigynium) (fig. 14) _ 12. Carex, p. 98.

Figure 12. Figure 13.

1. Dulichium L. C. Rich.

D. arundinaceum (L.) Britton — This species is distributed over
most of our area, and seems to prefer acid situations, at least in the
Coastal Plain,

2. Cyperus [Tourn.J L.

1. Achenes lenticular, 2-sided 1. C. flavescens.

1. Achenes triangular in x-section, 3-sided 2.

2. Plants perennial; bases hardened, corm-like, or 3.

stoloniferous.
2. Plants annual; bases not hardened or stolonif- 2. C. erythrorhizos.
erous.
3. Scales of spikelets deciduous, falling away from the 4.
rachilla of the spikelet.

88 ftTBLIC HEALTH BULLETIN NO. 286

3. Whole spikelet falling away from the main rachis 3. C. strigosus.

4. Stems naked below; rachilla of spikelet winged_ 4. C. haapan.

4. Stems leafy below , 5.

5. Achenes narrowly ellipsoid; scales of spikelet about 2.5 5. C. virens.

mm. long.

5. Achenes linear; scales of spikelet about 2 mm. long 6. C. pseudovegetus.

1 . C. flavescens L. — Shallow water and muddy places over most
of the Southeast, frequent.

2. C. erythrorhizos Muhl. — Also distributed over most of our
territory.

3. C. strigosus L. — Common over all of the Southeast, sometunes
in deeper water than the preceding.

4. C. haspan L. — Often truly aquatic, seems to prefer acid situations.
Coastal Plain, Florida north and west to beyond the limits of our
territory.

5. C. virens Michx. — Collected from aquatic areas near the coast in
Georgia, range includes all of our Coastal Plain.

6. C. pseudovegetus Steud. — Fairly common in shallow waters,
mostly in Coastal Plain, Florida north and west to beyond the limits
of om- area. In addition to the six species of Cyperus here enumerated,
there are several others which may occasionally be found in aquatic
habitats.

3. Fimbristylis Vahl

1. Achene lenticular __^ 1. F. annua.

1. Achene 3-angled 2.

2. Spikelets subglobose 2. F. miliacea.

2. Spikelets narrowly linear 3. F. autumnalis.

1. F. annua (All.) R. & S. — Noted in shallow water along the
coast, introduced Coastal Plain species, Florida to Georgia and west-
ward to beyond the limits of our territory.

2. F. miliacea Vahl — Introduced species, collected by the senior
writer from several stations near the coast in Georgia, also known to
occur in North Florida.

3. F. autumnalis (L.) R. & S. — Common over all of our territoiy.
Variety mucronulata (Michx.) Fernald is the only form which the
writers have encountered. There are in addition perhaps one or two
unlisted species of this genus which may occasionally be found in
fresh water.

4. Eleocharis R. Brown

1. Spikelets little or no thicker than the stem; scales 2,

mostly leathery.
1. Spikelets much thicker than the stem; scales mostly 7.
membraneous.

2. Stem with definite septa making it appear 3.

nodose.
2. Stem not nodose-septate 4.

A GUIDE AND KEY TO AQUATIC PLANTS 89

3. Septa becoming much closer together near top of stem ; 1. E. inter stincta.

perianth-bristles longer than achene.
3. Septa evenly spaced ; perianth-bristles shorter than the 2. E. equisetoides.
achene.

4. Stem definitely 3 or 4-angled 5.

4. Stem round or sometimes flattened 6.

5. Stem 4- \ngled, stout, mostly over 2 mm. in diameter 3. E. quadrangulata.

5. Stem 3-angled, about 1 mm. in diameter 4. E. robbinsii.

6. Stem stout, round, over 2 mm. in diameter 5. E. cellulosa.

6. Stem round or sometimes flattened, about 1 6. E. elongata.
mm. in diameter.

7. Achenes lenticular; 2-sided 8.

7. Achenes 3-angled __ 12.

8. Tubercle of achene lamellif orm (plate-like) 7. E. obtusa.

8. Tubercle of achene not lamelliform 9.

9. Sheaths at base of stem firm at the apex 10.

9. Sheaths at base of stem membraneous at apex 13.

10. Plants perennial from elongated rootstocks 11.

10. Plants tufted and annual, without conspicu- 12.
ous rootstocks.
11. Tips of spikelet scales spreading; 2 or 3 non-fertile 8. E. smallii.

scales at base of spikelet.
1 1 . Tips of spikelet scales erect ; 1 non-fertile scale present 9. E. calva.
at base of spikelet and this entirely encircles the
base.

12. Achene 1 mm. long 10. E. geniculata.

12. Achene 0.5 mm. long 11. E.atropurpurea.

13. Mature achene olive colored 12. E. olivacea.

13. Mature achene black or deep-brown 13. E.flavescens.

14. Achene cancellate ; that is the surf ace formed 15.

into small cells.
14. Achene smooth, papillose, or irregularly 18.
ridged.

15. Achene with longitudinal ribs 14. E. acicularis.

15. Achene without longitudinal ribs 16.

16. Achene 1 mm. or less long; stems often 15. E. vivipara.

proliferous.
16. Achene at least 1.5 mm. long; stems not 17.
proliferous.

17. Tubercle as large as the achene or larger, mitre-like 1&. E. tuberculosa.

17. Tubercle smaller than achene, conic 17. E. tortilis.

18. Achenes shining, black, topped by a de- 18. E. melanocarpa.
pressed whitish tubercle.

18. Achenes not black 19.

19. Achenes with the 3 angles ribbed 19. E. tricostata.

19. Achenes with the angles not ribbed 20.

20. Spikelets obviously distichous; that is, scales 20. E. baldwinii.

of spikelets in 2-ranks.
20. Spikelets scales not 2-ranked 21. E.microcarpa.

1. E. interstincta (Vahl) R. & S. Spikerush — Tropical species
known from two Florida counties but probably occurs more widely in
that State. The senior writer collected it from marshes near Lake
Okeechobee in Glades County.

90 PUBLIC HEALTH BULLETIN NO. 2 86

2. E. equisetoides (Ell.) Torr. Knotted Spikerush — Chiefly
Coastal Plain, should occur over most of our territory. In Georgia
most often seen in acid, open ponds.

3. E. quadrangulata (Michx.) R. & S. Square-stemmed Spikerush —
Ponds and marshes, chiefly Coastal Plain. Not definitely recorded
from Florida, Alabama, or Mississippi, but may occur in these as well
as our other states. In Georgia found mostly along the coast but at
least one inland station, a grassy limesink, was observed.

4. E. robbinsii Cakes — Occurs widely on the Coastal Plain over all
of our territory, observed by the senior writer mostly in acid, open
limesink ponds.

5. E. cellulosa Torr. — Confined to areas along the coast in Flonda,
Georgia, Alississippi, and probably Alabama. In Florida frequently
seen in acid freshwater ponds just behind the dunes along the Gulf of
Mexico.

6. E. elongata Chapm. — Noted by the senior author with the pre-
ceding in the Gulf region of North Florida, and collected from the
Okefinokee Swamp and from acid, open limesinks in Georgia. Occurs
also in South Alabama, but its range in our territory is not extensive.

7. E. obtusa (Willd.) Schultes — One of the most frequent of our
Spikerushes, usually occurs at the margins of ponds or in swamps
and muddy places, range includes all of our territory.

8. E. smallii Britton — Northern range but recently collected from
Tennessee by Dr. H. K. Svenson in the Interior Low Plateaus. A
collection from Meadow Pond near Wilson Reservior in North
Alabama by T. F. Hall has been determined as this species by Dr.
Svenson, and it may prove to have an even wider distribution in our
territory.

9. E. calva Torr. — Known in our area from Florida (no locality
given on collection). South Carolina, and Middle Tennessee. It, too,
may prove to have an even wider distribution, as it is difficult to
identify.

10. E. geniculata (L.) R. & S. — Usually not strictly aquatic but
occurs marginal to freshwater areas in Florida and has been recorded
once from South Carolina.

11. i?. atropurpurea (Retz.) Kunth — Has been recorded from wet
places in the Coastal Plain of Georgia and Florida.

12. E. olivacea Torr. — Infrequent, not seen by the writers. Has
been collected so seldom in the Southeast that it is difficult to charac-
terize its distribution.

13. E. flavescens (Poir.) Urban— Coastal Plain, most frequently
along the coast, Florida north and west to the limits of our territory.

14. E. acicularis R. & S. — Rare in our territory but occurs in most
of the States. The senior author collected it once from an acid, open
limesink pond in South Georgia.

A GUIDE AND KEY TO AQUATIC PLANTS 91

15. E. vivipara Link — Very rarely flowers and so is difficult to
identify, forms proliferating mats at the surface of ponds, very likely
more common than the records indicate. Coastal Plain in distribu-
tion, range extends beyond the limits of our territory, not definitely
recorded from Alabama or Mississippi.

16. E. tuberculosa (Michx.) R. & S. — One of the most frequent of
the Coastal Plain Spikerushes, easily identified by the enormous
tubercle of its achene. Usually in very shallow water or in moist
marginal situations, often in acid soil, range includes all of our Coastal
Plain.

17. E. tortilis (Link) Schultes — Much less common than the pre-
ceding, primaiily Coastal Plain but also in the Piedmont over most
of our territory.

18. E. melanocarpa Torr. — Distinctive species, known only from
South Georgia and North Florida, perhaps because of a lack of data.
It has been observed mostly in acid situations.

19. E. tricostata Torr. — Coastal Plain, South Georgia and North
Florida, also known beyond the limits of our territory.

20. E. haldioinii (Torr.) Chapm. — Collected frequently only in
Florida and South Georgia, single record for North Carolina. Fre-
quents mostly pine-barrens, noted proliferating in open, grassy lime-
sink ponds.

21. E. microcarva Torr. — Has been collected from all of our States,
common in acid moist places in the Coastal Plain. It has two well-
marked varieties which are more wide-ranging than the typical plant.

5. Scirpus L.

1. Inflorescence subtended by .a single leaf or none, this 2.

bract appearing like a continuation of the stem.

1. Inflorescence subtended by 2 or more bracts, leaf- 8.
like.

2. Spikelets 1 1. S. subterminalis.

2. Spikelets 2-numerous 3.

3. Spikelets 2-12, appearing lateral, not in umbel-like 4.
clusters.

3. Spikelets in umbel-like clusters, numerous 6.

4. Plants annual; scapes not sharply 3-angled 2. S. debilis.

4. Plants perennial ; scapes sharply 3-angled 5.

5. Scales of spikelet awned, bract much surpass- 3. S. americanus.

ing inflorescence; spikelet acute.

5. Scales of spikelet mucronate; bract only 4. S. olneyi.

slightly surpassing the inflorescence; spike-
lets obtuse.

6. Stems sharply 3-angled; leaves (also 3- 5. S. etuberculalvs.

angled) as long as scape.
0. Stems round; leaves reduced to mere sheaths. . 7.

92 PUBLIC HEALTH BULLETIN NO. 286

7. Achene gray, reddish, or black, abruptly acuminate 6. S. validus.

7. Achene nearly white, narrowed to short tip 7. *S. californicus.

8. Spikelets crowded into 1-several globose 8. S. cubensis.
heads.

8. Spikelets not crowded into globose heads 9.

9. Perianth-bristles downwardly barbed or wanting 10.

9. Perianth-bristles smooth or occasionally with a few 13.
ascending hairs.

10. Perianth-bristles wanting 9. S. georgianus.

10. Perianth-bristles present 11.

11. Perianth-bristles twice as long as the achene 10. S. polyphyllus.

1 1 . Perianth-bristles not exceeding achene in length 12.

12. Spikelets 3-8 in each head; scales obtuse; II. S. sylvaticus.
lower leaf -sheaths red-tinged; perianth-
bristles barbed to base.
12. Spikelets 8-20 in each head; scales acute; 12. S. atrovirens.
lower leaf -sheaths green; perianth-bristles
not barbed near base.
13. Perianth-bristles at maturity scarcely if at all exceed- 14.

ing the scales.
13. Perianth-bristles at maturity greatly exceeding scales 13, S. eriophorum.
making spikelet appear wooly.
14. Perianth-bristles about equalling achene; 15.

scales acute.
14. Perianth-bristles about twice as long as 14. S. lineatus.
achene; scales mucronate.
15. Spikelets 1 mm. thick; achene not papillose; inflores- 15. S. divaricatus.

cence terminal only.
15. Spikelets 2-3 mm. thick; achenes papillose; inflores- 16. S.fontinalis.
cence terminal and lateral.

1. S. subterminalis Torr. — Probably occurs in western part of our
range, not noted by the writers.

2. S. debilis Pursh — Swamps mostly in the northern parts of our
territory.

3. S. americanus Pers.. Three-square Bulrush — Should occur over
all of our territory, uncommon except along the coast, noted in
marshes in the Everglades of Florida.

4. S. olneyi A. Gray — Supposed to occur in our territory from
Florida north but not observed by the writers. Probably will be found
along the coast.

5. S. etuberculatus (Steud.) Kuntze — Mostly Coastal Plain, in
acid limesinks in Georgia and South Carolina, not frequent, ranges
from Florida north and west to beyond the limits of our territory.

6. S. validusY&hl. Great Bulrush — Range covers all of our territory,
observed mostly along the coast, but occurs in hard waters inland.

7. S. californicus (C. A. Meyer) Britton — Similar in appearance to
the preceding, occurs in the southernmost part of our territory from
Florida westward, common in marshes along some parts of the Gulf of
Mexico.

A GUIDE AND KEY TO AQUATIC PLANTS 93

8. S. cubensis Poepp. and Kunth — Introduced species, simulating
Cyperus, found in the southernmost part of our territory from Florida
westward.

9. S. georgianus Harper — Swamps in the northern part of our terri-
tory. Some authorities consider it merely a variety of S. atrovirens
(#12).

10. S. polyphyllus Vahl — Range similar to preceding but more
common.

l\. S. sylvaticus L. — Also present only in the northern part of our
territory.

12. S. atrovirens Muhl. — Another of the more northerly ranging
group of Scirpus. None of the preceding four has been encountered
often in the Coastal Plain by the writers.

13. S. eriophorum Michx. Wool-grass — Very frequent in our
territory in a variety of aquatic situations. Has been found in
extremely acid places, in alluvial swamps, and basic artesian ponds.
Its close relative, S. cyperinus (L.) Kunth, with sessile instead of
pedicelled spikelets, may be present in the northern part of our
territory. Its range includes aU of our States.

14. S. lineatus Michx. — Range includes all of our territory, should
^ccur in swamps.

15. S. divaricatus Ell. — Mostly in swamps of creeks and rivers in
the Coastal Plain, Florida north and west to beyond the limits of our
territory.

16. S.fontinalis Harper — Known in our territory only from springy
pond margins in the Coastal Plain of Georgia, may occur more widely
for a variety of the species has recently been described from the
Virginia Coastal Plain.

6. Fuirena Rottb.

1. Leaves reduced to mere sheaths 1. F . scir-poidea.

1. Leaves with well-developed blades 2.

2. Plants annual, without rhizomes; perianth- 2. F.pumila.

bristles equalling or exceeding the achene.
2. Plants perennial, with rhizomes; perianth- 3.
bristles only reaching the middle of achene or
shorter.
3. Perianth-bristles very short, not exceeding the stipe of 3. F. breviseta.

the achene; perianth-scales orbicular or reniform.
3. Perianth-bristles reaching the middle of the achene; 4. F. squarrosa.
perianth scales deltoid-ovate

1. F. scirpoidea Michx. — Strictly Coastal Plain in distribution,
Florida, South Georgia, and probably South Alabama and Mississippi.
A similar species, F. longa Chapm. in which the upper leaf-sheaths
bear leaves, occurs from West Florida to Mississippi but is not defi-
nitely aquatic.

94 PUBLIC HEALTH BULLETIN NO. 2 86

2. F. pumila Torr. Umbrella-grass — Mostly of Coastal Plain distri-
bution, supposed to occur most frequently in brackish marshes, but
collected from acid pond margins. Ranges from Florida to north of our
territory.

3. F. breviseta Coville — Common in Coastal Plain, Florida north and
west to the limits of our territory.

4. F. squarrosa Miclix. — Difficult to distinguish superficially from
the preceding. Found also in acid places, Coastal Plain, Florida north
and west to beyond the limits of our territory.

7. Dichromena Michx.

1. Bracts subtending flower clusters 4-6, linear; lubercle 1. D. color ala.

not decurrent on the sides of the achene.

1. Bracts 7-10, lanceolate; tubercle decurrent on sides of 2. D. laiifolia.

achene.

1. D. colorata, (L.) Hitchc. White-top Rush — Coastal Plain,
Florida north and west to beyond the limits of our territory in less
acid situations than the following species. Common along tbe coast.

2. D. latifolia Baldw. — Range similar to preceding, habitat more

acid.

8. Psilocarya Torr.

1. Tubercle higher than wide, as long or nearly as long as 1. P. corymbifera.

achene, somewhat decurrent.
1. Tubercle broader than long, much shorter than acliene, 2. P. niUns.

not decurrent.

1. P. corymbifera (C. Wright) Britton — Ajound ponds in acid situa-
tions. Coastal Plain, Florida, Georgia, and probably Alabama and
Mississippi.

2. P. nitens (Vahl) Wood. Bald-rush— Similar situations to the above
but more widespread, Florida north and west to beyond the limits of
our territory. A third species, P. scirpoides Torr., may enter our
territory in North Carolina, and the senior writer has one or two
Georgia specimens which have been determined as this.

9. Rhynchospora Vahl

1. Tubercle of achene over twice as long as achene 2.

1. Tubercle as long as achene or shorter ^ 6.

2. Tubercle very slender over all; spikelets in 1. R. tracyi.

1-4 dense, globose heads.
2. Tubercle broadened at the ba.se, narrowed 3.
upward; spikelets pedicelled,

3, Perianth-bristles sliorter than achene- . 2. R. corniculata.

3. Perianth-bristles much longer than achene 4.

4. Plant not stoionifcrou.s; spikelets in clusters 3. R. macrostachya.

of 10-50 together.
4. Plant stoloniferous; spikelets few in each 5.
cluster.

A GUIDE AND KET TO AQUATIC PLANTS

95

13.
13.

15.
15.

17.
17.

ly.

19.

21.
21.

23.
23.

Aclicne eliipsoid-obovate, much longer than wide 4. R. inundala.

Achene broidly-obovate, slightly longer than wide 5. R. careyana.

6. Perianth- bristles wanting or very short 7.

6. Perianth-bristles well-developed 8.

Achene transversely wrinkled.. 6. R. intermixta.

Achene smooth 7. R. chopmanii.

8. Perianth-bristles downwardly barbed 9.

8. Perianth-bristles upwardly barbed 13.

Clusters of spikelets loo^e . 10.

Spikelets ir dense globose heads 11.

10. Achene 1.5-2 mm. long; panicles rather loose; 8. R. glomerata.
if achene is 1.5 mm. long .spikelets 2-3 flow-
ered.
10. Achene 1.5 mm. long, panicles dense; spikelets 9. R. chalarocephala,
with 1 perfect flower.

Acheiies 2.5 mm. long; spikelets 5-6 n^rn. long 10. R. cephalnntha.

Achenes about 1.5 mm. long; spikelets .3-3.5 mm. long_ 12.

12. Heads not truly globose, not tightly com- 9. R. chalarocephala.
pacted; basal leaves 1-2 mm. wide, invo-
lute.
12. Heads very compact and globo.se; basal 11.7?. microcephala.
leaves 1.5-3 ram. wide, flat.
Achenes smooth or cancellate, not transversely 14.
wrinkled.

Achenes transversely w rinkled 20.

14, Achenes cancellate 12. R. harveyi.

14. Achenes smooth 15.

Tubercle of achene serrulate to ciliate 16.

T u bercle of achene smoot h or gran ular 18.

16. Achene 1 mm. long, light bro\vn 13. R. filifolia.

16. Achene 1.5-2 mm. long, dark brown 17.

Achenes narrowly obovoid, much less than 1 mm. 14. R. fusca.
wide.

Achene broadly obovoid, about 1 mm. wide. . 15. /?. harperi.

18. Perianth-bristles much longer than achene. _ 16. R. gracilenla.
18. Perianth-bristles much shorter than achene.. 19.

Leaf-blades linear; spikelets 4-5 mm. long . 17. R. fascicularis.

Leaf-blades bristle-like, filiform; spikelets 2.5-3 mm. 18. R. wrightiana.
long.

20. Perianth-bristles shorter than the achene 21.

20. Perianth-bristles as long as achene or longer 26.

Leaf-blades involute 19. R. torreyana^

Leaf-blades flat 22.

22, Achene biconvex, not constricted under 23.

tubercle.
22. Achene compressed, constricted under 20. R. compressu.
tubercle.

Achene 1 mm. long; tubercle wider than high 24.

Achene 1.5 mm. long; tubercle about as long as wide 21. R. cymosa.

24. Achene ellipsoidal, manifestly longer than 22. R. edisoniana.

broad, finely wTinkled.
24. Achene nearly orbicular, about as long as 25.
broad, coarsely wrinkled.

96 PUBLIC HEALTH BULLETIN NO. 286

25. Inflorescence with many spikelets, more or less nodd- 23. R. perplexa.

ing; tubercle confluent with achene body.
25. Inflorescence with few spikelets; tubercle with a ring- 24. R. globularis.
like base, sharply differentiated from achene body.

26. Achene constricted at base to a stipe 25. R.stipiiata.

26. Achene not stipitate 27.

27. Clusters of spikelets on erect or ascending stalks 28.

27. Clusters of spikelets with divaricate stalks. 26. R.miliacea.

28. Tubercle not setose 29.

28. Tubercle setose 31.

29. Perianth-bristles about as long as achene but shorter 30.

than tubercle.
29. Perianth-bristles as long as achene and tubercle 27. R.schoenoides.

30. Tubercle blunt, achene orbicular 28. R. rrdcrocarpa.

30. Tubercle sharp-pointed, achene ellipsoidal 20. R.decurrens.

31. Perianth-bristles not longer than achene and tubercle. _ 30. R.patula.
31. Perianth-bristles longer than achene and tubercle 32.

32. Achene broadly obovoid or orbicular obovold- 31. R.caduca.

32. Achene narrowly obovoid 32. R, mixta.

1. R. tracyi Britton — Coastal Plain pineland ponds and swamps,
Florida to Georgia and Mississippi.

2. R. corniculata (Lam.) A. Gray — Mostly on the Coastal Plain
over most of our territory. A variety, interior Fernald, is found in the
western part of our range.

3. R. wucrostachya Torr. — Found in a variety of aquatic situations,
range includes all of our territory.

4. R. inundata (Oakes) Fernald — Coastal Plain, probably most
common in the eastern part of our territory.

5. R. careyana Fernald — Coastal Plain, recorded in the literature
only from Florida. The- senior author has collected it also in South
Georgia.

6. R. intermixta C. Wright — Piueland ponds and swamps in the
southern part of our territory, Florida westward along the Gulf to
beyond the limits of our territory.

7. R. chapmanii M. A. Cm-tis — Coastal Plain in acid situations,
Florida to North Carolina and Louisiana.

8. R. glomerata (L.) Vahl — As used here, includes R. capitellata
(Michx.) Vahl and R. lepiocarpa (Chapm.) Small. Ranges over all of
our territory, conunon mostly in acid situations especially in the
Coastal Plain.

9. R. chalarocephala Fernald & Gale — Recently described species,
acid ponds, Virginia south to South Carolina. May prove to have a
wider distribution.

10. R. cephalantha A. Gray — Acid ponds and swamps, Coastal Plain,
over most of our territory.

11. .R. microcephala Britton — Similar species, distribution very like
that of the preceding.

A GUIDE AND KEY TO AQUATIC PLANTS 97

12. R. harveyi W. Boott — Georgia to Virginia and westward,
infrequent.

13. R.JilifoliaToTT. — Acid ponds in the pine-barrens, Coastal Plain,
Florida to North Carolina and westward along the Gulf to beyond the
limit of our territory.

14. R.fusca (L.) Ait. f. — Distribution similar to that of the preced-
ing.

15. R. harperi Small — Known only from pineland ponds in the
Coastal Plain of Georgia.

16. R. gracilenta A. Gt&j — Acid ponds and swamps, mostly in the
Coastal Plain, Florida north and west beyond the limits of our terri-
tory. One of the more frequent species of the genus.

17. R. Jascicularis (Michx.) Vahl — Low pinelands and pineland
ponds, Coastal Plain, Florida to North Carolina and westward to the
limit of our range.

18. R. wrightiana Boeckl. — Coastal Plain in acid situations, Florida
north to North Carolina.

19. R. torreyana A. Gray — Acid swamps, Coastal Plain, Georgia to
the northern limit of our territory.

20. R. compressa Carey — Pineland ponds. Coastal Plain, Florida to
Georgia and westward.

21. R. cymosa Ell. — Various provinces, range covers all of our
territory.

22. R. edisoniana Britton — Ponds and swamps of peninsular Florida.

23. R. perplexa Britton — Coastal Plain swamps, Florida to North
Carolina and Louisiana.

24. R. globularis (Chapm.) Small — Coastal Plain pinelands, Florida
north and west to the limits of our territory.

25. R. stipitata Chapm. — Coastal Plain pineland swamps, Florida
to North Carolina and Louisiana.

26. R. miliacea (Lam.) A. Gray — Pond margins mostly in calcareous
areas. Coastal Plain, Florida to North Carolina and Louisiana.

27. R. schoenoides (Ell.) Britton — Pond margins. Coastal Plain,
Florida to North Carolina and Louisiana.

28. R. microcarpa Baldw. — Acid pineland ponds. Coastal Plain,
Florida to North Carolina and westward along the Gulf to beyond the
limits of our territory.

29.' R. decurrens Chapm. — Known only from swamps in West
Florida.

30. R. patula A. Gray — Acid pineland swamps. Coastal Plain,
Florida north to North Carolina and west to Mississippi.

31. R. caduca Ell. — Swamps, mostly Coastal Plain, Florida to
North Carolina and west beyond the limits of territory.

32. R. mixta Britton — Coastal Plain swamps and ponds, Florida to
Georgia and westward beyond the limit of our range.

98 PUBLIC HEALTH BULLETIN NO. 2 86

10. Cladium P. Browne

1. Leaves smooth and unarmed l.C mariscoides.

1. Leaves spinulose on margins and midribs beneath 2. C. jamaicensis.

1. C. mariscoides (Mulil.) Torr. — Not observed by the writers, but
supposed to occur south to Florida in our territory,

2. C. jamaicensis Crantz. Saw-grass — The famous vicious Saw-
grass of the Everglades, occurs also along the coast to the limits of our
territory. Most common in Florida and along the Gulf of Mexico
in fresh to brackish situations. Both of these species are placed in the
genus Mariscus by Small.

11. Scleria Berg.

1. Achene bearing a disk-like body (hypogynum) below __ 2.

1. Achene without a hypogynum 3.

2. Achene body reticulate 1. <S. muhlenhergii.

2. Achene body papillose 2. S. pavciflora.

3. Spikelets in a single terminal cluster 4.

3. Spikelets in several distant clusters along the upper 5.
part of the stem.

4. Achene 3 mm. long or less with a pair of 3. S. georgiana.

prominent pits on each side of base.

4. Achene over 3 mm. long, without prominent 4. S. haldwinii.
pits on each side of base.

5. Achene papillose-ridged; bracts merely serrulate near 5. *S'. verticillata.

apex.

5. Achene smooth; bracts with long spreading hairs near 6. S. hirtella.
apex.

1. S. muhlenhergii Steud.^ — Acid aquatic areas, should be well dis-
tributed over our territory, especially in the Coastal plain.

2. S. pauciflora Muhl. — Should be distributed much as the preced-
ing.

3. (S. georgiana Core — Acid places. Coastal Plain, north m our
territory to South Carolina. Cited by Small, as aS. gracilis Ell.

4. S'. haldwinii (Torr.) Steud. — Coastal Plain, found only in the
Southernmost part of our territory from Florida westward along the
Gulf.

5. S. verticillata Muhl. — Coastal Plain, Florida north and west
beyond the limits of our territory.

6. S. hirtella Swartz — Coastal Plain, north only to South Carolina
but westward beyond the hmits of our range.

12. Carex jRupp.] L.

1. Acheiie.s lenticvilar; styles 2 2.

1 . Achenes 3-sided ; styles 3__ ..... 11.

2. Lateral spikes sessile 3.

2. Lateral .spikes stalked \. C. stricta.

3. Spikes with staminate floxrers uppermost 4.

3. Spikes with pistillate Uowers uppermost (lower spikes

sometimes all pistillate) ._ .- 6.

A GUIDE AND KEY TO AQUATIC PLANTS 99

4. Perigynium abruptly contracted to a beak 5.

4. Perigynium gradually narrowed to a beak 0.

5. Perigynium yellowish: opaque part of leaf-sheath

transver.sely-\v'rinkled . 2. C. vulpinoidea.

5. Perigynium bro'vnish; opaque part of leaf-sheath nut

wrinkled - . 3. C. decomposita.

('). Wing of perigj'nium abruptly narrowed near

the middle of body A . C . tribuloides .

6. Wing of perigynium not narrowed near middle

of body . 7.

7. Scales of spikelet obtuse or acute; acheues not slenderly

stipitate - 8.

7. Scales of spikelet long-accuminate to aristate; achenes

slenderly stipitate 5. C. alala.

8. Tips of perigynia appressed 6. C. longii.

8. Tips of perigynia spreading ._ ._ 7. C albolutescens .

9. Perigynium 4 to 6 mm. long, without a disk-like base;
beak I to 2 times length of body; leaf-sheaths not

red-dotted within 10.

0. Perigynium 6 to 7 mm. long, with a hard disk-like
base; beak 2-3 times length of body; leaf-sheaths

red-dotted within . . . S. C. crus-corvi.

10. Sheaths transversely wrinkled within, easily

broken, not thickened at mouth. . 9. C. stipata.

iO. Sheaths not transversely wrinkled within, not

easily broken, thickened at mouth 10. C. laevi-vaginata.

11. Lowest bract strongly green-sheathing; beak of peri-
gynium bidentate, but with weak teeth il. C cherokeensis.

1 1 . Lowest bract not strongly green-sheathing, or if so peri-
gynium with strongl}' bidentate apex with stiff teelh_ 12.

12. Perigynium beakless or very short beaked 13.

12. Perigynium strongly beaked; beak strongly

bidentate 17.

]?v. Terminal spike, if staminate, without rough-awned

scales 14.

13. Terminal spike staminate; scales rough-awned 15.

14. Terminal spike staminate; lateral spikes slen-
der-stalked, the lower drooping; pistillate
scales obtuse or acute, shorter than the

perigynia_. 12. C. hnrrattii.

14. Terminal .spike with pistillate .lowers upper-
most; lateral spikes short-stalked or sessile,
erect; pistillate scales strongly awned, ex-
ceeding the perigynia 13. C. buxbuamii.

lo. Perigynium strongly ribbed; staminate scales gradu-
ally awned . 14. C. joorii.

15. Perigynium nerved; staminate Scales abruptly awned_ 16.
16. Pistillate spikes erect; perigynium strongly-
nerved 15. C. verrucosa.

16. Pistillate spikes nodding; perigynium ob-
scurely nerved 16. C. glaucescens.

17. Style jointed with achene 17. C. walteriana.

17. Style continuous with achene 18.

100

PUBLIC HEALTH BULLETIN NO. 286

18. Perigynium coriaceous with impressed nerves. 18. C hyalinolepis.
18. Perigynium membranous, the nerves or ribs 19.
not impressed.
19. Perigynium lanceolate, tapering into the beak, many 20.

nerved.
19. Perigynium broader; abruptly contracted into the 21.
beak, usually strongly ribbed.

20. Perigynium teeth reflexed, green 19. C. colUnsii.

20. Perigynium teeth not reflexed, yellowish- 20. C. lonchocarpa.
green.

21. Perigynium less than 1 cm. long 22.

21 . Perigynium more than 1 cm. long 26.

22. Perigynium body ovoid or globose, but not 23.

truncately contracted into beak.
22. Perigynium body obovoid or obconic, trun- 20.
cately contracted into the prominent
beak.

23. Perigynium coarsely ribbed or nerveless 24.

23. Perigynium finely and closely ribbed 21. C. comosa.

24. Pistillate scales rough-awned 22. C. lurida.

24. Pistillate scales not rough-awned 25.

25. Perigynium abruptly beaked, strongly inflated; pistil- 23. C. bullata.

late spikes 20-40 flowered.
25. Perigynium less abruptly beaked, not strongly in- 24. C. elliottii.
flated; spikes 10-20 flowered

26. Pistillate spikes globose or subglobose; style 27.

straight; stolons short, ascending.
26. Pistillate spikes oblong or cylindric; style 28.
abruptly bent; stolons long, horizontal.
27. Perigynium rounded at base, shining; leaf-blades 2.5-8 25. C. intumescena.
mm. wide, their sheaths short prolonged upward at
mouth beyond base of leaf-blade.
27. Perigynium cuneate at base, dull, often hispidulous; 26. C. grayi.
leaf-blades 4.5-14 mm. wide; sheath not prolonged.
28. -Perigynium ascending; beak less than twice 29.

length of body.
28. Perigynium spreading at right angles to spike 27. C. gigantea.
axis; beak 2-3 times length of body.

29. Stems in tufts; leaf-blades 4-12 mm. wide 28. C. lupulina.

29. Stems arising singly from elongate rootstock; leaf- 29. C. louisianica.
blades 2-5 mm. wide.

30. Scales exceeding perigynia; achenes about 30. C. frankii.

1.5 mm. long.
30. Scales much shorter than perigynia; achenes 31.
2.2-3 mm. long.
31. Beaks of perigynia appressed ascending; style straight 31. C. iyphina.

below; achenes obovoid with concave sides.
31. Beaks of perigynia widely radiating; style strongly 32. C. squarrosa.
curved or bent below; achenes linear-oval with flat
sides.

1. C. stricta Lam. — This tussock- forming species and its variety
strictior (Dewey) Carey occur only in the most northern part of our

A GUIDE AND KEY TO AQUATIC PLANTS 101

territory. The related C. torta Boott is found in our territory but
was not included because it does not inhabit still waters.

2. C. vulpinoidea Michx. — Moist places, various provinces over
most of our territory.

3. C. decomposita Muhl. — Rare species, various provinces, south
to Florida. Collected from logs in Reelfoot Lake, Tennessee, by the
senior author.

4. C. tribuloides Wahlenb. — Various provinces over all of our
territory.

5. C. alata Torr. — Supposed to occur mostly along the coast or in
calcareous regions mostly in the Coastal Plain, over all of our territory.

6. C. longii Mackenzie — Coastal Plain, apparently prefering acid
situations, should be found in most of our states.

7. C. albolutescens Schk. — Range includes all of our territory.

8. C. crus-corvi Shuttlw. — Enters our territory from the west
but is found all the way to Florida, seems to prefer neutral soils.

9. C. stipiata Muhl. — This includes also variety maxima Bailey
which is the frequent form in our territory. Occurs in neutral soils
and has been collected from alluvial areas.

10. C. laevi-vaginata (Kukenth.) Mackenzie — Should range over
most of our territory but has not been noted by the writers.

11. C. cherokeensis Schwein. — Swamps, Coastal Plain, Florida to
Georgia and westward.

12. C. barrattii Schwein. & Torr. — Said to occur in very acid swamps
and bogs, Coastal Plain, south to North Carolina.

13. C. buxbaumii Wahlenb.— Said to occur in swamps in calcareous
regions, various provinces, south to Georgia. Neither this nor the
preceding species has been noted by the ■writers.

14. C. joorii Bailey- — Coastal Plain, Florida to South Carolina and
westward in acid cypress ponds and swamps.

15. C. verrucosa Muhl. — Coastal Plain in acid ponds and swamps,
distribution almost identical to preceding in our territory.

16. C. glaucescens FAl. — Acid ponds and swamps. Coastal Plain,
perhaps more common than the two preceding species. Range
similar, but found northward to Virginia.

17. C. walteriana Bailey — Acid ponds and swamps, Coastal Plain,
in the eastern part of our territory south to Florida. A related species
C. lanuginosa Michx. may enter our territory in the north.

18. C. hyalinolepis Steud. — Neutral swamps over most of our area.
The closely related C. riparia Curtis variety lacustris (Willd.) Kukenth.
enters our territory in Tennessee.

19. C. collinsii Nutt. — Very acid swamps, Coastal Plain, in the
eastern portion of our range from Georgia north.

102 PUBLIC HEALTH BULLETIN NO. 2 86

20. C. lonchocarpa Willd; — Swamps, Coastal Plain, Florida to
South Carolina and westward. The closely related C. folliculata L.
also probably enters our territory in the north.

21. C. comosa Boott — Swamps, various provinces, Florida north.
Collected by the senior author 'in our territory mostly in alluvial
situations.

22. C. lujida Wahlenb. — Swampy areas, over all of our territory.
Apparently has no marked soil preference and is ver}^ frequent.

23. C. bullata Schk. — Coastal Plain in the eastern part of our area.
Has been taken from river swamps but is said to occur in acid, swampy
meadows.

24. C. elliottii Schw^eni & Torr. — Coastal Plain, Florida to Alabama
and North Carolina in very acid places, infrequent.

25. C. intumescens liudge— Branch swamps aiid river swamps,
various provinces over all of our range.

26. C. grayi Bailey — Various provinces, Georgia north, seeming to
prefer neutral soils.

27. C. gigantea Rudge—Acid ponds or swamps, Coastal Plain and
occasionally adjacent provinces over most of our territory.

28. C. lupulina Muhl.^ — Swamps, various provinces, over all of our
territory.

29. C. louisianica Bailey — Said to occur mostly in the Coastal
Plain, range includes all of our territory.

30. C.frankii Kunth — Northern part of our territory m calcareous
soils.

31. C. typhina Michx. — Most characteristic of calcareous districts,
various provinces, Georgia north and west.

32. C. squarrosa L. — Mostly in the northern part of our territory-
being known from North Carolina and Tennessee. There is one
recorded occurrence in a river swamp in the Coastal Plain of Georgia.
In addition to the above 32 species of Carex there are perhaps a few
others which are either only occasionally aquatic or which enter our
range in its northern part.

ARACEAE Arum family

1, Acorus L.

A. calamus L. Sweet-flag — Various provinces, range should include
all of our area, but vcr}^ i]i frequent.

1. Orontium L.

0. aquaticum L. Never-wet — Most frequently found along sluggish
creeks or rivers or in alluvial swamps, also present in the very acid
Okefinokee Swamp and in other non-alluvial aquatic situations.
Range covers all of the Coastal Plain of our territory. Anopheles
quadrimaculatus can often be found associated.

A GUIDE AND KEY TO AQUATIC PLANTS 103

3. Peltandra Raf.

1. Spathe narrow, green throughout; fruits green 1. P. virginica.

1. Spathe broad and spreading, mostly white; fruits 2. P. glauca.
crimson.

1. P. virginica (L.) Kunth Arrow-arum — Well distributed in
swamps and shallow water over all of our territory, frequent.

2. P. glauca (Ell.) Feay. Wliite Arrow-arum— Very acid swamps
or ponds, Coastal Plain, Florida to Alabama and North Carolina.
Not nearly as frequent as the preceding.

4. Pistia L.

P. stratiotes L. Water-Lettuce — Floating plant very often forming
a complete carpet oa streams, lakes and ponds in the Coastal Plain in
Florida. Found westward to Louisiana and may be present in Ala-
bama and Mississippi. It is very often in association with species of
Mansonia.

LEMNACEAE Duckweed family

1. Wolffia Horkel

1 . Plant rounded on back ; not covered with minute brown

dots. 1- W. Columbiana.

1. Plant flat on back ; covered with minute brown dots 2. W. punctata.

1. W. Columbiana Karst. Watermeal — Smallest, with the next, of
our flowering plants. When abundant, they form a granular layer on
the surface of ponds or lakes. Both this and the following species are
well distributed over our territory.

2. W. punctata Griseb. Watermeal^ All that has been said of the
preceding applies to this species except that it has not been as fre-
quently noted. These two species are listed under Bruneria by Small.

2. Wolffiella Hegel

W.jioridana (J. D. Smith) C. H. Thompson. Bog-mat — Very com-
mon, even in very acid waters, in the Coastal Plain of our territory.
It has been taken as far north as Reelfoot Lake, Tennessee, in the
Mississippi Valley.

3. Lemna L.

1. Joints or disks long, narrow and stalked; plants com- 1. L. trisulca.

monly forming masses below surface of water.

1. Joints not stalked; floating on surface of water 2.

2. Joints symmetrical or nearly so 3.

2. Joints asymmetrical 4.

3. Joints elliptic-obovate 2-4 ram. long; fruit lenticular 2. L. minor.

3. Joints elliptic or oblong 1.5-3.9 mm. long; fruit elongate. 3. L. minima.

104 PUBLIC HEALTH BULLETIN NO. 286

4. Joints with unequally rounded sides, thick, 3- 4. L. perpusilla,

nerved or -veined.
4. Joints with parallel sides, thin, 1-nerved or 6. L. valdiviana.

-veined.

1. L. trisulca L. Star Duckweed — Found in only the western part
of our territory, not noted by the writers.

2. L. minor L. Duckweed — Extremely difficult to distinguish from
the following species except in fruit, and fruits very rarely in nature.
The range of this species includes all of our territory, and it is common.
A dense covering of this plant often inhibits mosquito breeding, but
partial growths often harbor Anopheles quadrimaculatus larvae.

3. L. minima Philippi — The remarks under the preceding apply
aUke to this species, although its distribution is probably more limited.

4. L. perpusilla Torr. — Ponds, range includes all of our territory.

5. L. valdiviana Philippi — The remarks under the preceding species
apply also to this.

4. Spirodela Schleid.

S. polyrhiza (L.) Schleid. — This easily recognized, large Duckweed
occurs over practically all of our territory and is very frequent. It
has often been foimd in association with Anopheles quadrimaculatus
except when in dense, blanket-like growth.

MAYACACEAE Bog-moss family

1. Mayaca Aubl.

1. Stalks of flowers much longer than the leaves 1. M. aubletii.

1 . Stalks shorter than the leaves 2, M. fiuviatilis.

1. M. aubleti Michx. Bog-moss — Ranges over most of our Coastal
Plain, generally in acid ponds.

2. M. fiuviatilis Aubl. — Range more restricted, known only from
Florida to Georgia and Mississippi. Much less frequent than the
preceding species and is considered by some to be only a form of it.

XYRIDACEAE Yellow-eyed Grass famUy

1. Xyris [Gronov.] L.

1. Leaves round, filiform; sterile filaments glabrous 1. X. baldmniana.

1 . Leaves flat ; sterile filaments bearded 2.

2. Lateral sepals included under bracts 3.

2. Lateral sepals partially exserted 11.

3. Keel or wing of the lateral sepal ciliate 4.

3. Keel or wing of the lateral sepal incised, cross-toothed 6.
or lacerate.

4. Lateral sepals winged, the wing partially 5.

ciliate, not bearded.

4. Lateral sepals keeled, the keel mainly cilio- 2. X. torta.
late its entire length, bearded at the apex.

A GUIDE AND KEY TO AQUATIC PLANTS 105

5. Sepal wing narrow, narrower than the sepal body 3. X. amhigua.

5. Sepal wing broad, broader than the sepal body 4. X. stricta.

6. Keel or wing cross-toothed or incised 7.

6. Keel or wing lacerate 9.

7. Spike ovoid, oval or globular, 5-15 mm. long at 8.

maturity; scales in relatively few series.
7. Spikes oblong to conic-oblong, 16-23 mm. long at 5. X. elata.
maturity; scales in many series.

8. Bracts loosely imbricate in few series, decid- 6. X. caroliniana.

uous.
8. Bracts closely imbricate in several series, 7. X. jupacai.
persistent.
9. Lateral sepals crested from about the middle or just 10.

below it to the apex, the crest erect or nearly so.
9. Lateral sepals crested from the base to the apex, the 8. X. iridifolia.
crest spreading or partially recurved.

10. Spike acute; lateral sepals with the wing nar- 9. X. difformis.
row or obsolete near the base; leaves and
scape smooth.
10. Spike obtuse; lateral sepals with the wing 10. X. serotina.
broad to the base; leaves and scape rough-
margined.
11. Leaves numerous, blades mostly 1-2 mm. wide at 11. A', elliottii.

maturity.
11. Leaves few; blades mostly 5-10 mm. wide at maturity— 12.

12. Crest of the lateral sepals of very short erect 12. X. smalliana.

segments; upper part of scape smooth.
12. Crest of the lateral sepals of very long spread- 13. X. fimbriata.
ing segments; upper part of scape rough.

1. X. haldwiniana R. & S. St. Marys-grass — Coastal Plain pine-
land ponds, Florida to North Carolina and westward to beyond our
boundary.

2. X. torta J. E. Smith— Of more northern distribution, various
provinces, Georgia north and west.

3. X. amhigua Beyr. — Swamps in the Coastal Plain, Florida to
North Carolina and westward along the Gulf to beyond the limit of
our territory.

4. X. stricta Chapm. — More southernly in its distribution. Found
around pineland pools. Coastal Plain, Florida to Mississippi along the
Gulf of Mexico.

5. X. elata Chapm. — Florida northward and westward to the limits
of our range in Coastal Plain swamps and ponds.

6. X. caroliniana Walt. Yellow-eyed Grass — Shallow ponds and
swamps, often very acid, Coastal Plain, Florida north and west to the
limits of our territory.

7. X. jupacai Rich. — Distribution very similar to the preceding.
Called X. communis Kunth in many manuals.

8. X. iridifolia Chapm. — Shallow ponds, Florida to Georgia and
westward mostly in the Coastal Plain.

106 PUBLIC HEALTH BULLETIN NO. 286

9. X. diformis Chapm. — Swamps, Coastal Plain, Florida, Georgia,
and Alabama.

10. X. serotina Chapm. — Known only from pineland swamps in
Florida and Mississippi.

11. X. elliottii Chapm. — Pinelands and swamps, Florida to Virginia
in the Coastal Plain.

12. X. smalliana Nash — Acid ponds, Coastal Plain, Florida to South
Carolina and west to the limit of our territory. Not as common as
the following.

13. X.Jimhriata Ell. — Acid ponds or swamps, Coastal Plain, Florida
to Mississippi and northward to the limit of our ranga.

ERIOCAULACEAE Pipewort family

1. Eriocaulon [Gronov.] L.

1. Flower heads, when mature, white villous at summit 2.

I. Flower heads, when mature, brown or blackish 1. E. ravenein.

2. Flower heads less than 10 mm. in diameter 2. E. lineare.

when mature; scape 3-5 ridged.
2. Flower heads more than 10 mm. in diameter 3.
when mature; scape 10-14 ridged.
3, Sheath at base of scape surpassing leaves except when 3. E. compressum.

plant is submerged; flowers March- April.
3. Sheath at base of scape surpassed by leaves; flowers 4. E. decangulare.
June-September.

1. E. ravenelii Chapm. — Swamps, Coastal Plain, Florida to Mis-
sissippi and South Carolina. Apparently the most infrequent oi
the genus.

2. E. lineare Small — Mostly in Coastal Plain pinelands but occa-
sionally in acid swamps or ponds, Florida, Alabama, and Georgia.

3. E. compressum Lam. Pipewort — The species of Eriocaulon most
frequently found in truly aquatic situations. Occurs in acid ponds
in the Coastal Plain over most of our territory.

4. E. decangulare L. — Most often found in pine-barrens but occa-
sionally in acid swamps, range similar to that of the preceding species.

PONTEDERIACEAE Pickerel-weed family

1. Heteranthera R. & P.

1. Leaves ribbon-like ^ 1. H. duhia.

1. Leaves broad 2.

2. Leaves as wide as long, lobed at base 2. H. reniformis.

2. Leaves longer than wide obtuse at both ends, _ 3. H. limosa.

1. H. duhia (Jacq.) MacM. Water Star-grass — Ponds or lakes,
various provmces, over all of our territory. Apparently prefers
neutral or alkaline waters, and Anojjheles guadrimaculatus is some-
times found associated.

A GUIDE AND KEY TO AQUATIC PLANTS 107

2. H. reniformis R. & P. Mud-plantain — Georgia northward and
westward, like others of the genus seeming to prefer neutral or alka-
line waters.

3. H. limosa (Swartz) Willd. — Range embraces all of our territory,
but not common.

2. Pontederia L.

P. lanceolata Nutt. Pickerel-weed — All of the Pickerel-weeds ob-
served by the writers in our territory are included under this species,
although it may be that P. cordata L. could also be differentiated.
One of the most frequent aquatic plants over most of our range and
found in a wide variety of aquatic situations. The shape of its
leaves varies considerably from linear to very broad and lobed at
the base.

3. Eichhornia Kunth

E. crassipes (Mart.) Solms. Water Hyacinth — Coastal Plain, over
most of our territory, but most abundant in Florida, Georgia, and
westward along the Gulf. In Florida is occasionally so abundant as
to impede navigation. Often grows in enormous pure masses and can
be found in association with Anopheles quadrimaculatus. Another
species, E. paniculatus (Spreng.) Solms, is said to occur in peninsular
Florida.

JUNCACEAE Rush family

1. Juncus [Tourn.] L.

1. Plants creeping or forming mats in or OD the surface of 1. J. re-pens.

the water.

1. Plants erect and emergent 2.

2. Stem appearing to continue upward beyond 3.

inflorescence.

2. Inflorescence terminal 4,

3. Sheaths at base of stem without leaf-blades 2. J. effusus.

3. Sheaths at base of stem with round blades 3. /. coriaceus

4. Leaves with node-like septa 6.

4. Leaves flat without node-like septa 5.

5. Heads of inflorescence 5-15 flowered; heads usually 4. J. marginaius.

few.

5. Heads of inflorescence 2-5 flowered; heads usually 5. J. hiflorus.
many.

6. Clusters reduced to only a single flower 6. J. abortivus.

6. Clusters of inflorescence with many flowers 7.

7. Capsule truly subulate 8.

7. Capsule ellipsoid to linear-lanceolate in outline some- 11.
times acute or mucronate at apex but not truly
subulate.

8. Uppermost leaf-sheath with very short blade 7. J. megacephalus.

or none (at most 1-2 cm. long).

8. Uppermost leaf-sheath with well-developed 9.
blade (3 cm. long or more).

108 PUBLIC HEALTH BULLETIN NO. 286

9. Stamens as long as petals, the anthers exserted be- 8. J. scirpoides.
tween them.

9. Stamens much shorter than petals, included 10.

10. Leaf-blades flattened and usually with incom- 9. J. polycephalus.

plete septa; capsule manifestly beaked.

10. Leaf-blades only slightly compressed; septa 10. J. validus.
complete; capsule beakless.

11. Capsule not more than two-thirds as long as perianth. 11. J. brachycarpus.

11. Capsule equalling or exceeding the perianth 12.

12. Seed 0.7-2.5 mm. long, the body tapering 13.

at both ends into a white tail.

12. Seed less than 0.55 mm. long with an abrupt 14.
usually dark colored tail.

13. Capsule scarcely exceeding perianth; plant not rigid-. 12. /. canadensis.

13. Capsule exceeding perianth by about half its length; 13. J. trigonocarpus.
plant rigid throughout.

14. Capsule exceeding the perianth 15.

14. Capsule about equalling the perianth 14. J . acuminatus.

15. Capsule dark brown at maturity 15. J.elliottii.

15. Capsule straw-colored at maturity 16. J. debilis.

1. J. repens Michx. — Various provinces over all of our territory,
most common in the Coastal Plain, in very acid as well as nearly
neutral waters. It has often been found in association with Anoph-
eles quadrimaculatus.

2. J. effusus L. Soft-rush — Perhaps the most frequent species
of the genus in our territory. Shows wide tolerance of acidity and
has been found in association with Anopheles quadrimaculatus.

3. J. coriaceus Mackenzie — Like the preceding ranges over all of
our territory, but infrequent and usually confined to springy places.

4. J. marginatus Rostk. — Various provinces over all of our territory
but noted most frequently near the coast.

5. J. bifiorus Ell. — Ranges over all our territory. Collected in
very acid as well as almost neutral situations.

6. J. ahortivus Chapm. — Coastal Plain, along margins of ponds,
middle Florida to South Carolina.

7. J. megacephalus M. A. Curtis — Coastal Plain, Florida to Vir-
ginia, mostly in calcareous situations.

8. J. scirpoides Lam. — Occurs over all of our Coastal Plain terri-
tory, fairly frequent and often in very acid situations.

9. J. polycephalus Michx. — Ponds and swamps, Coastal Plain over
most of our range.

10. J. validus Coville — Should occur only in the westernmost portion
of our Coastal Plain; however, the senior author has one collection
from South Florida.

11. J. brachycarpus Engelm. — Various provinces, Georgia north-
ward and westward. Collected from neutral soil in west Tennessee.

12. J. canadensis J. Gay — Various situations, range similar to the
preceding.

A GUIDE AND KEY TO AQUATIC PLANTS 109

13. J. trigonocarpus Steud. — Acid preferring plant, Coastal Plain,
Florida to South Carolina and along the Gulf westward at least to
Mississippi.

14. J. acuminaius Michx. — Various provinces, Georgia north and
west. Seems to show no particular preference as to acidity.

15. J. elliottii Chapm. — Coastal Plain, acid swamps or bogs,
Florida to North Carolina and westward to the western limit of our
territory.

16. J. debilis A. Gray — Various provinces over most of our territory.

SMILACACEi^E Smilax family

1. Smilax [Tourn.] L.

1. Berries red; leaves not leathery, usually not much 1. S. walteri.

longer than broad.
1. Berries black; leaves leathery, usually much longer 2. S. laurifolia.

than broad.

1. S. walteri Pursh. Coral Greenbrier — Vine of pineland ponds and
swamps. Coastal Plain over most of our territory.

2. S. laurifolia L. Bamboo-vine — Non-alluvial, acid swamps,
Coastal Plain, Florida northward and westward to the limits of our
territory.

AMARYLLIDACEAE AmaryUis family

1. Crinum L.

C. americanum L. — Extreme southern Coastal Plain, Florida west-
ward along the Gulf to beyond the limits of our territory.

2. Hymenocallis L.

1. Sepals and petals green; stalk terminated by a single 1. H. palmeri.

flower.
1 . Sepals and petals white; stalk terminated by 2 to many 2.
flowers.

2. Stalk terminated by 8-16 flowers; crown small, 2. H. kimballiae.

2.5-3.5 cm. wide.
2. Stalk terminated by 2-8 flowers; crown at least 3.
4 cm. wide.
3. Filaments arising from a sinus, sometimes very shallow, 4.
between the lobes or angles of the crown; filaments
not arising from a 2-pronged lobe.
3. Filaments arising from a 2-pronged lobe of the crown 3. H. laciniata.
with a sinus intervening between filaments.

4. Edge of crown between the filaments erose 4. H. crassifolia.

4. Edge of crown between the filaments wath 3, 5. H. tridentata.
sometimes 5, teeth.

1. //. palmeri S. Wats. Alligator Lily — Found only in the Ever-
glades region of Florida.

no

PUBLIC HEALTH BULLETIN NO. 2 86

2. H. kimhalliae Small — Known only from swamps around the
estuary of the Apalachicola River in West Florida.

3. H. laciniata Small — Known from swamps in North Florida.

4. H. crassifolia Herb. — Marshes on the Coastal Plain, northeast
Florida to North Carolina.

5. H. tridentata Small — Known only from swamps along the east
coast in Florida.

IRIDACEAE Iris family

1, Nemastylis Nutt.

N. Jloridana Small — Swamps and marshes, known only from the
northeastern coastal region of Florida.

2. Iris L.
1. Flowers coppery red 1. I.fulva.

1. Flowers violet, lilac, bluish, or white 2.

2. Petals present and well-developed, nearly as 3.

long as the sepals.
2. Petals present but almost rudimentary, much 2. I. tripetala.
exceeded by sepals.

3. Hypanthium 6-angled 4.

3. Hypanthium 3-angled 7.

4. Capsule sharply 6-angled, flowering stalk zig- 5.

zag.
4. Capsule bluntly 6-angled, flowering stalks
neaily straight.
5. Style-appendages half -ovate; claw of sepal yellow-
green without; foliage yellow-green.
5. Style-appendages lanceolate; claw of sepal deep-green
without; foliage deep-green.

6. Flowers white, exfcept the yellow crest 5. /. albispiritus.

6. Flowers colored 6. I. savannarum.

7. Capsule and hypanthium sharply 3-angled; rootstock 7. /. prismatica.

wiry, slender.
7. Capsule and hypanthium bluntly 3-angled; rootstock
stout and fleshy.

8. Petals shorter than the styles; sepals rough-
ened at base of blade with minute bumps, and
with a dull yellow spot; outermost bracts
with margins darkened and somewhat var-
nished; seeds regularly pitted and appearing
as if varnished.
8. Petals longer than the styles; sepals hairy at
the base of blade and with a bright yellow
spot; outermost bracts green and soft-
margined; seeds irregularly or not at all
pitted, dull.

1. /. fulva Ker. Wild Iris — Most common in the western portion
of our territory, but said to be found east as far as Georgia.

2. /. tripetala Walt. Wild Iris — Coastal Plain, North Florida to
North Carolina, seeming to prefer acid situations.

6.

3. /. hexagona.

4. I. rivularis.

8.

8. I. versicolor.

9. /. virginica.

A GUIDE AND KEY TO AQUATIC PLANTS 111

3. /. hexagona Walt. — Coastal Plain, North Florida to South
Carolina. Small has described /. alabamensis from marshes in west
Central Alabama which is similar to this.

4. /. rimilaris Small — Coastal Plain, Northeast Florida to the ad-
joining portion of Georgia.

5. /. albispiritus Small — White species, most common on savannas
in th« lower half of the Florida peninsula.

6. /. savannarum Small — Also an inhabitant of savannas of penin-
sular Florida.

7. /. prismatica Pursh — Marshes and swamps, Coastal Plain,
Georgia to the northern hmits of our territory, often in acid situations.

8. /. versicolor L. — Marshes and swamps in our territory from Georgia
west to Mississippi and north to the limit of our range.

9. /. mrginica L.7— Range similar to the preceding except also
known from North Florida.

HAEMODORACEAE Bloodwort family

1. Gyrotheca Salisb.

G. tinctoria (Walt.) Salisb. Paint-root — Acid situations, Coastal
Plain, Florida north a ad west to the limits of our territory.

CANNACEAE Canna family
1. Canna L.

C.flaccida Salisb. Golden Canna — Infrequent plant of swamps and
marshes. Coastal Plain, Florida to South Carolina.

MARANTACEAE Arrowroot family
1. Thalia L.

1. Flowers closely crowded on the stalk; clusters of bracts 1. T. dealbata.

and bractlets ovoid.
1. Flowers separated on the stalk; clusters of bracts and 2. T. geniculata.

bractlets narrowly conic.

1. T. dealbata Roscoe — Infrequent in swamps and ponds. Coastal
Plain, Florida to South Carolina and along the Gu)f to th*^ western
limit of our territory.

2. T. geniculata L. — Largest-leaved aquatic herb; in fact, the
largest-leaved of all native herbs. The plants stand 2 to 3.5 meters
high. Its range is restricted to ponds, swamps, and marshes in
Florida.

112 PXTBLIC HEALTH BULLETIN NO. 2 86

ORCHID ACEAE Orchid famUy
1. Habenaria Willd.

H. repens Nutt. — Acid swamps and ponds, Coastal Plain, Florida
to North Carolina and westward.

PIPERACEAE Pepper family
1. Saururus L.

S. cemuus L. Lizards-tail — This emergent plant is well distributed
over all of our area. Its habitat is very variable, but it is frequently
found in truly aquatic areas. It shows a wide acidity tolerance and
is found in acid and alkaline regions alike. It is very often found in
association with Anopheles quadrimaculatus and in some instances
constitutes a major problem.

JUGLAND ACEAE Wahiut family
1. Carya Nutt.

C. aquatica (Michx. f .) Nutt. Swamp Hickory — River-swamps and
river-bottoms mostly in the Coastal Plain, Florida north and west to
the limits of our territory.

MYRICACEAE Bayberry family

1. Myrica L.

1. Fruit 2-3 mm. in diameter; leaves long-attenuate to the 1. M. cerifera.

base, acute at apex.
1. Fruit 3.5-4 mm. in diameter; leaves not long-attenu<ate 2. M. caroUnensis.

to base, apex obtuse.

1. M. cerifera L. Wax Myrtle — Occasionally in swamps but is
more frequently in non-aquatic situations over all of our Coastal
Plain territory.

2. M. carolinensis Mill. Bayberry — Acid swamps and other non-
aquatic situations over most of our Coastal Plain territory.

SALICACEAE Willow family

1. Salix [Tourn.] L.

1. Leaves closely and finely toothed 2.

1. Leaves with remote teeth 1. S. interior.

2. Leaves green beneath 2. S. nigra.

2. Leaves glaucous or sU very-white beneath 3.

3. Twigs brittle-jointed 3. S. harbisonii.

3. Twigs not brittle-jointed 4. S. longipes.

1. S. interior Rowlee. Sandbar Willow — Alluvial areas in the
Mississippi Valley, aquatic mostly during periods of high water.

A GUIDE AND KEY TO AQUATIC PLANTS 113

2. S. nigra Marsh. Black Willow — The common swamp willow
over all of our territory. It is often found in situations also favored
by Anopheles quadrimaculatus .

3. S. harbisonii Schneider — Swamps in our territory from North
Carolina south to Florida. Apparently has been most frequently
collected from along rivers. It has been suspected of being a hybrid
between the preceding and following species.

4. S. Icngipes Shuttle w. — Swamps and along streams mostly in the
Coastal Plain. Its range embraces/all of our Coastal Plain territory.
S. amphibia Small, described from lakes and swamps in peninsular
Florida, should be referred to this species.

BETULACEAE Birch family

1. Betula [Tourn.] L.

B. nigra L. River Birch — Swamps of streams over all of our
range. Unmistakable because of its reddish, papery bark.

2. Alnus [Tourn.] L.

A. sirrulaia WiUd. Alder — Swamps along branches, creeks and
rivers in various provinces, range covers all of our territory. This
species is commonly referred to as Alnus rugosa (Du Roi) Spreng.

URTICACEAE Nettle family
1. Boehmeria Jacq.

1. Leaf-blades leathery, finely toothed; petioles much 1. B. drummondiana.

shorter than the blades.
1. Leaf-blades thin, coarsely toothed; petioles as long as 2. B. cylindrica.

the blades or only slightly shorter.

1. B. drummondiana Wedd. Bog-hemp — Swamps in various prov-
inces, range includes all of our territory.

2. B. cylindrica (L.) WUld. — Distribution in our territory about
the same as the preceding, but apparently more common.

ULMACEAE Elm family

1. Planera J. F. Gmel.

P. aquaiica (Walt.) J. F. Gmel. Water Elm— Swamps along rivers,
range covers most of our Coastal Plain and Mississippi Valley terri-
tory.

POLYGONACEAE Buckwheat family

1. Rumex L.

1. Leaf-blades short and broad, rounded or cordate at \. R. fascicularis.

base; sepal-wings toothed.
1. Leaf-blades narrow and elongate, narrowed to the base; 2. R. verticillatus.

sepal wings undulate.

114 PUBLIC HEALTH BULLETIN NO. 286

1. R. fascicvlaris Small — Around ponds and in prairies in peninsular
Florida.

2. R. verticiUatus L. Swamp-dock — Common mostly in swamps of
rivers or creeks, various provinces over all of our territory. Laivae
of Anojyheles quadrimaculaius have been found associated with this
plant.

2. Polygonum [Toiirn.] L.

1. Stems armed with prickles; leaves lobed at base 1. P. sagittatum.

1. Stems not armed with prickles 2.

2. Stem terminated by a single (sometimes 2) 2. P. coccineum.
cluster of flowers; no axillary inflores-
cences present.
2. Clusters of flowers axillary as well as terminal, 3.
more than 2 and usually several.
3. Ocreae (sheaths on stem just above bases of leaves) 4.
not fringed with bristles.

3. Ocreae fringed with bristles 7.

4. Flower clusters erect 5.

4. Flower clusters nodding, slender 3. P. lapathifolmm.

5. Plant perennial; achene turgid-lenticular; flowers 4. P. densiflorum.
usually white or whitish, with tinj' dark dots when
viewed with lens.
5. Plant annual; achene flat; flowers usually pink, not 6.
dotted.

6. Style or stamens conspicuously longer than 5. P. longistylum.
the perianth.

6. Style or stamens hidden by the perianth 6. P. pensylvanicuni .

7. Perianth showing tiny dark dots when viewed with a 8.

lens.
7. Perianth not showing tiny dark dots when viewed 9.
with a lens.

8. Achene granular, dull; flower clusters often 7. P. hydropiper.

nodding.
8. Achene smooth, shining; flower clusters erect- 8. P. punclatum.

9. Flower cluster short, stout, compact 9. P. persicaria.

9. Flower cluster slender, not dense 10.

10. Leaves cordate or subcordate at base, sessile; 10. P. hirsutum.

stem and ocreae hairy.
10. Leaves narrowed to a petiole at base; stem 11.
and ocreae not hairy.
11. Leaves tapering to both ends from a point well below 11. P. setaceum.
the middle covered with stiff" hairs.

11. Leaves with nearly parallel sides usually not hairy 12.

12. Spike loose; the white or pink perianth com- 12. P. hydro piperoides.

pletely hiding the mature nutlet.
12. Spike more dense; the green perianth not 13. P. opelousanum.
hiding the tip of the mature achene.

1. P. sagittatum L. Rakestraw — Moist places over all of our terri-
tory.

2. P. coccineum Muhl. — Occurs widely in our territory, but infre-
quent. Seems to prefer alluvial situations. This and the following
11 species are listed under the genus Persicaria by Small.

A GUIDE AND KEY TO AQUATIC PLANTS 115

3. P. lapathifolium L. — Most common in alluvial marshes and
swamps along rivers, range covering all of our territory. It has on
occasion been found in association with Anopheles quadrimacvlatus.

4. P. densiflorum Meisn. — Range includes all of our Coastal Plain.
Said to be found in swamps, ponds, and along lake-borders.

5. P. longisiylum Small — Should be expected only in the extreme
western part of our territory.

6. P. pensylvanicum L. Smartweed — Distributed over all of om*
territory, both in aquatic and non-aquatic situations. Most com-
mon, perhaps, in alluvial marshes and Anopheles quadrimaculatus has
been found associated with it occasionally.

7. P. hydropiper L. Water-pepper — Ranges over all of our terri-
tory, often not truly aquatic. When found in water, generally
prefers neutral or alkaline conditions.

8. P. pundatum Ell. — Shows a wide acidity tolerance and, like
many of this genus, is equally at home in the water and on land.
Range covers all of our territory, and breeding of Anopheles quadri-
maadatus has occasionally been found associated with it.

9. P. persicaria L. — Most often found on land, occasionally truly
aquatic. Range includes all of our territory.

10. P. hirsuium Walt. — Coastal Plain, Florida and Georgia.
Collected from acid limesink ponds and other very acid situations.

11. P. setaceum Baldw.— This Water-pepper is found over all of
our Coastal Plain. The writers have encountered it most frequently
in acid situations.

12. P. hydropiperoides Michx. — Various provinces over all of our
territory. Anopheles quadrimaculatus found associated with it at
Reelfoot Lake, Tennessee.

13. P. opelousanum Ridd. — Various provinces over all of our terri-
tory. The writers have not often noted it owing to its similarity to
the preceding species.

AMARANTHACEAE Amaranth family
1. Acnida L,

A. cuspidata Bertero — Huge herb, the largest in our flora, found in
marshes and swamps, Coastal Plain, Florida to Louisiana. The stem
at the base of the plant sometimes reaches over a foot in diameter.

2. Alternanthera Forsk.

A. philoieroides (Mart.) Griseb. Alligator-grass — Pestiferous spe-
cies, naturalized from South America and often found in alluvial areas.
Found in a variety of aquatic areas. Coastal Plain, Florida to North
Carolina and westward. In the Tennessee Valley it has become
introduced and verv often harbors larvae oi Anopheles quadrimacidatus.
This species is listed by SmaU under the genus Achyranthes.

116 PUBLIC HEALTH BULLETIN NO. 2 86

CERATOPHYLLACEAE Hornwort family

1. Ceratophyllum L.

1. Achene armed on the edges with spines, long-beaked.. 1. C. demersum.
1. Achene unarmed, short-beaked 2. C. submersum.

1. C. demersum L. Coontail-moss — Various provinces, over all of
our territory. Most often found in neutral or alkaline waters, although
tolerating some degree of acidity. Anopheles guadrimaculatus has
been found associated with it. Variety echinatum A. Gray is sometimes
given specific rank.

2. C. submersum L. — Found only in ponds on the southern part of
the peninsula of Florida.

NIMPHAEACEAE Water-lily famUy

1. Nuphar Sibth.

1. Leaf-blades more than twice as long as wide, the sinus 2.

less than one-fourth the length of the blade.
1. Leaf-blades less than twice as long as wide, the sinus 3.
one-fourth to one-half the length of the blade.

2. Leaf-blades over 3 times as long as wide, the 1. N. sagittaefolia.

sinus open.
2. Leaf-blades less than 3 times as long as wide, 2. A^. ulvacea,
the sinus closed.

3. Leaves pubescent beneath 4.

3. Leaves glabrous beneath 5.

4. Leaf-blade with a closed sinus; stamens in 9-10 3. N. orbiculata.
rows; flowers about 5 cm. in diameter; seed
4 mm. long.
4. Leaf -blade with an open sinus; stamens in 6-7 4. A^. bombycina.
rows; flowers about 7 cm. in diameter; seed 6
mm. long.

5. Leaf-blades of an orbicular or ovate-orbicular type 5. N. fluviatile.

5. Leaf-blades manifestly longer than wide 6.

6. Leaf-blades very thin; submersed leaves present- 6. N. chartacea.
6. Leaf-blades thick; submersed leaves absent 7. N. advena.

1. N. sagittaefolium (Walt.) Pursh. Cow-lily- — Sluggish streams,
Coastal North and South Carolina and Virginia. This and the follow-
ing six species are all listed by Small under Nymphaea.

2. N. ulvaceum (Miller & Standley) Standley — Sluggish streams
in West Florida. Possibly this is what has been recorded as N.
sagittaefolium from Alabama.

3. N. orbiculatum (Small) Standley — Lakes and ponds from Middle
Florida to Southernmost Georgia.

4. N. bombycinum (Miller & Standley) Standley — Ponds in the
Coastal Plain, North Florida and adjacent Georgia. The senior
author has collected it from acid limesinks in South Georgia, near
the South Carolina line.

A GUIDE AND KEY TO AQUATIC PLANTS 117

5. A^. Jlumatile (Harper) Standley — Coastal Plain, West Florida
to Alabama and North Carolina. Usually occurs in connection with
streams or rivers, but may be found in perfectly still water.

6. A^. chartaceum (Miller & Standley) Standley — Ponds near the
Gulf from Florida to Mississippi.

7. N. advena Ait. Cow-lily — Most widely distributed and most
frequent species of the genus. Range covers all of our States and is
often found in alluvial situations. Nymphaea macrophylla Small
is included in this consideration of A^. advena.

2. Nymphaea L.

1. Flowers white 1. N. odorata.

1. Flowers blue or yellow 2.

2. Flowers blue 2. N. elegans.

2. Flowers yellow 3. N.flava.

1. A^. odorata Ait. White Water-lily — Distributed over all of our
territoiy and very frequent. Shows an extremely wide acidity
tolerance, being found in tlie most acid and the most alkaline waters
alike. This and the two following species are listed under Castalia
by Small's Manual.

2. N. elegans Hook. Blue Water-lily — Big Cypress Swamp,
Florida, but may be introduced at other pdLnts.

3. N. jlava Leitner. Yellow Water-lily — Known only from lakes,
ponds, and slow streams on the peninsula of Florida.

3. Cabomba Aubl.

C. caroliniana A. Gray. Fanwort — Mat-forming species, distrib-
uted over most of our territory, but not frequent in most portions.
Perhaps most often found in alluvial aquatic areas.

4. Brasenia Schreb.

B. schreberi Gmel. Water-shield — Well distributed in a variety
of aquatic situations, its range covering all of our territory. Col-
lected from alluvial marshes and swamps, as well as from very acid
limesink ponds. Some investigators have found a negative correla-
tion with Anopheles quadrimaculatus.

5. Nelumbo Adams.

A^. lutea (Willd.) Pers. Lotus, Water-chinquapin — Well distributed
over the Coastal Plain, collected or noted in a variety of situations by
the writers. Grows in acid limesinks, alluvial marshes, and other
aquatic areas where it is not indigenous (for instance, borrow pits and
artesian impoundments). In the Tennessee Valley it is often found

118 PUBLIC HEALTH BULLETIN NO. 286

in association with Anopheles quadrimaculatus. The pink-flowered
N. nucifera Gaertn. has been noted as introduced in two localities in
Georgia.

RANUNCULACEAE Crowfoot family

1. Caltha [Rupp.] L.

C. palustris L. Marsh-marigold — May possibly come into our
territory in its northern part. Prefers calcareous situations.

2. Myosurus L.

M. minimus L. Mouse-tail — Margin? of aquatic areas, various
provinces, its range covering all of our territory. Apparently prefers
calcareous soils.

3. Ranunculus [Tourn.] L.

1. Leaves cut into many thread-like or ribbon-like divi- \. R. fiahellaris.

sions.

1. Leaves entire or lobed but not cut into divisions as 2.
above.

2. Leaves narrow, nearly linear, not lobed 3.

2. Leaves broad, deeply lobed 2. R. sceleratus.

3. Plants perennial; stems creeping; achene with a subvi- 3. R. ambigens.
late beak.

3. Plants annual; stems not creeping; achene beakless 4.

4. Petals mostly over 3 mm. long 4. R. laxicaulis.

4. Petals mostly less than 3 mm. long 5.

5. Achene papillose 5. R. lindheimeri.

5. Achene smooth ^ ^_ 6. R. piisillus.

1. R. flabellaris'R&f. Water Buttercup —In our territory only along
the Mississippi River Valley in Tennessee and North Mississippi unless
possibly in North Carolina. This is the R. delphinifolius Torr. of
Small's Manual.

2. R. sceleratus L. — Introduced species, its range including all of
our territory. The senior author has noted it only in aUuvial situa-
tions in the Mississippi River Valley.

3. R. ambigens S. Wats.^ — Should be expected only in the northern
part of our territory. Listed as R. obtusiusculus Raf. by Small.

4. R. laxicaulis (T. & G.) Darby — Moist places in the Coastal
Plain and occasionally other provinces, its range including all of our
territory.

5. R. lindheimeri Engelm.— Ponds from Alabama westward to
beyond our Imiits.

6. R. pusillus Poir. — Wet places over all of our territory.

A GUIDE AND KEY TO AQUATIC PLANTS 119

MAGNOLIACEAE Magnolia family

1. Magnolia L.

M. virginiajia L. — This tree (sometimes shrub) is found over all of
our Coastal Plain and seems to prefer acid soils.

CRUCIFERAE Mustard family

1. Rorippa Scop.

R. sessilijiora (Nutt.) Hitchc. Water-cress — Various provinces,
Florida north and west to beyond the limits of om* territory. The
senior writer has collected it from ponds in the Mississippi Valley in
Tennessee and Mississippi. This species is listed under Radicula by
Small.

2. Neobeckia Greene

A^. aquatica (A. Eaton) Britton. Lake-cress — Said to range over
most of our territory but noted by the WTiters only in the western
portion.

3. Nasturtium R. Brown

N. officinale R. Brown. Water-cress — Very variable species, rang-
ing over all of our territory from Georgia north and west, particularly
in springy places. Tliis species is called Sisymbrium Nasturtium-
Aquaticum L. by Small.

CRASSULACEAE Orpine family
1. Penthorum [Gronov.] L.

P. sedoides L. Ditch Stonecrop — Swamps and ponds usually in
association with streams, over all of our territory.

ITEACEAE Virginia willow family

1. Itea [Gronov.] L.

/. mrginica L. Virginia Willow — Ranges over most of our Coastal
Plain and is occasionally foimd in the Piedmont, most often in asso-
ciation with creeks or small streams.

ROSACEAE Rose famUy
1. Rosa [Tourn.] L.

R. palustris Marsh. Swamp Rose^ — Swamps and ponds over ahnost
all of our territory.

120 PUBLIC HEALTH BULLETIN NO. 286

MALACEAE Apple famUy

1. Crataegus L.

C. aestivalis (Walt.) T. & G. Mayhaw — Ponds and perhaps along
streams, Florida to South Carolma and westward beyond the Hmits
of our region. In Southwest Georgia it is the dominant species in
temporary ponds of solution origin.

LEGUMINOSAE Pea famHy

1. Gleditsia L.

G. aquatica Marsh. Swamp Locust — River-swamps, Florida to
South Carolina and westward in the Coastal Plain. Very common in
the valley of the Mississippi River. May easily be distinguished from
the similar G. tricanthos L. by the oval, single-seeded pod.

2. Amorpha L.

A. jruticosa L. Indigo-bush — Common in swamps in non-acid
regions, ranging over all of our territory. A glabrous species, A.
nitens F. E. Boynton, has been described from swamps near Waynes-
boro, Georgia, and a few of the other species of Amorpha may occasion-
ally grow in wet places.

POLYGALACEAE MUkwort famUy

1. Polygala L.

1. Flower clusters compound; that is, made up of several

clusters 2.

1 . Flowers in a single terminal cluster 4.

2, Flowers yellow 3.

2. Flowers white 1. P. baldwini.

3. Capsule round, seed about 0.5 mm. long 2. P. ramosa.

3. Capsule 2-lobed, seed about 1 mm. long 3. P. cymosa.

4. Flowers brilliant orange 4. P. lutea.

4. Flowers lemon-yellow 5. P. rugelii.

1. P. haldwini Nutt. — Low pin elands and acid pineland swamps,
Coastal Plain, Florida to Georgia and Mississippi. This and the four
following species are listed under the genus Pilostaxis by Small.

2. P. ramosa Ell. — Situations similar to the above, but more wide-
spread, ranging north and west in the Coastal Plain to beyond the
limits of our territory.

3. P. cymosa Walt. — More truly aquatic than the preceding two or
the following species. Found in acid cypress ponds and pineland
pools over all of our Coastal Plam territory.

4. P. lutea L. — Acid moist places. Coastal Plain, Florida north and
west to beyond the limits of our territory.

5. P. rugelii Shuttlw. — Pineland swamps and ponds only in penin-
sular Florida.

A GUIDE AND KEY TO AQUATIC PLANTS 121

EUPHORBIACEAE Spurge famUy

1. Stillingia Garden

S. aquatica Chapm. — Low, short-lived shrub with extremely light
corky wood. Found infrequently in acid ponds and marshes, Coastal
Plain, Florida to South Carolina and Mississippi.

CALLITRICHACEAE Water Starwort family

1. Callitriche L.

1. Fruit longer than broad, lobes keeled 1. C. palustris.

1. Fruit as broad as long, lobes rounded on edges 2. C. heterophylla.

1. C. palustris L. Water Starwort — In ponds over all of our terri-
tory.

2. C. heterophylla Pursh. Water Starwort — Should also range over
all of our territory.

CYRILLACEAE Titi family
1. Cyrilla Garden

1. Leaves mostly over 5 cm. long; petals 3 mm. long or 1. C racemiflora.

more.
1. Leaves mostly less than 4 cm. long; petals less than 2. C. parvifolia.

3 mm. long.

1. C. racemiflora L. Titi — Acid swamps over all of our Coastal
Plain territory.

2. C. parvifolia Raf. Titi — Small-leafed species, found from North
Florida westward along the Gulf to beyond our limit.

2. Cliftonia Gaertn.

C. monophylla (Lam.) Sarg. Titi — Non-alluvial acid swamps in
the Coastal Plain, North Florida to Georgia and westward to beyond
the limit of our range.

AQUIFOLIACEAE Holly family

1. Ilex L.

1. Berry black 1. I. coriacea.

1. Berry red 2.

2. Leaf-blades linear, 1-4 cm. long 2. /. myrtifolia.

2. Leaf -blades elliptic, 4-10 cm. long 3. I. cassine.

1. I. coriacea (Pursh) Chapm. — Acid non-alluvial swamps, Coastal
Plain, Florida north and west to beyond the limits of our territory.

2. /. myrtifolia Walt. — Acid swamps and acid Cypress ponds,
Coastal Plain, Florida to North Carolina and to the westward beyond
the limit of our territory.

3. /. cassine L. Yaupon — Swamps, usually acid. Coastal Plain,
Florida north and west to beyond the limits of our region.

122 PUBLIC HEALTH BULLETIN NO. 2 86

ACERACEAE Maple family

1. Acjr L.

1. Leaves simple 2.

1. Leaves compound 1. A. negundo.

2. Leaf-bia,des glabrous or nearly so beneath 2. A. rvhrum.

2. Leaf-blades wooly beneath 3. A. drv.vimondii.

1. A. negundo L. Ash-!eaved Maple — River-swamps (»ver ail of
our territory. This species is listed under the genus Negundo by
Small.

2. A. ruhrum L. Red Maple — Creek and river-swamps over all
of our territory. It and the following species are cited under the
generic name of Rufacer by Small.

3. A. drummondii Hook. & Arn. Red Maple— Perhaps most
common in the Mississippi Valley region but also occurring in river-
swamps from Florida to Georgia and westward. Sometimes con-
sidered as only a variety of the preceding.

RHAMNACEAE Buckthorn family
1. Berchemia Neck.

B. scandens (Hill) Trelease. Rattan-vine — Swamps of creeks and
rivers, mostly Coastal Plain, Florida north and west beyond the
limits of our range.

VITACEAE Grape family

1. Ampelopsis Michx.

A. arhorea (L.) Rusby. Pepper-vine — Swamps of the larger
rivers over all of our Coastal Plain and Mississippi Valley territory.

MALVACEAE Mallow family

1. Hibiscus L.

1. Flowers brilliant red 2.

1. Flowers pink or white 3.

2. Leaf -blades with 5-7 narrow elongate lobes 1. H. coccinevs.

2. Leaf-blades merely toothed or with 3-6 pronii- 2. H. semilohatus.
nent but short, broad lobes.

3. Leaf-blades glabrous 3. H. militaris.

3. Leaf -blades pubescent at least beneath 4.

4. Capsule glabrous 4. //. moschevios.

4. Capsule pubescent 5.

5. Capsule beaked 6.

5. Capsule rounded or truncate at top 5. H. lasiocarpus.

6. Leaf -blades lanceolate to ovate; toothed but 6. H. incanus.
not lobed.

6. Leaf -blades as broad as long, 3-5 lobed 7. H. grandiflorus.

1. H. coccineus Walt. — Swamps along the coast in Georgia,
Florida, and Alabama.

A GUIDE AND KEY TO AQUATIC PLANTS 123

2. H. semilobatus Cbapm. — Swamps, near the coast, East Florida.

3. H. militaris Cav. Rose Mallow — Alluvial swamps over all of
our territory.

4. H. moscheutos L. — Alarshes over all of our territory, especially
in alluvial areas.

5. H. lasiocarpus Cav. — Swamps, various provinces, Georgia west
to beyond the limits of our territory.

6. II. incanus Wendl. — Swamps, Coastal Plain, Florida and Ala-
bama north to beyond the limits of our territory.

7. H. grandiflorus Alichx. — Marshes, Coastal Plain, Florida to
Georgia and Mississippi.

HYPERICACEAE St. John's-wort family

1. Hypericum L.

1. Petals of flowers pink 2.

I. Petals of flowers yellow 3.

2. Filaments united only near the base; leaves 1. //. virginicum.

sessile and clamping.

2. Filaments united to near the middle; leaves 2. H. tuhulosum.
sessile and elusping or narrowed and petioled.

3. Plants with prominent stolons 3. H. adpressum.

3. Plants without prominent stolons 4.

4. Inflorescence without leaves 4. H. cistifolium.

4. Inflorescence leafy 5.

5. Leaves clasping at base, ovate to ovate-lanceolate 5. H. myrtifolium.

5. Leaves not clasping but narrowed at base. 6.

6. Leaves conspicuously whorled; leaves very nar- 6. H. galioides.

row, sometimes needle-like and not revolute.

6. Leaves not conspicuously whorled ; leaves 7. H. densifiorum .
usually not needle-like and revolute.

1. H. virginicum L. — Usually in acid swamps, ranging over most of
om* territory.

2. H. tuhulosum Walt. — Consists, in our territory, of two varieties,
the typical one and variety walteri (Gmel.) Lott. Tlie former has
broad based leaves while in the latter the leaves are narrowed to
petioles. Both seem to, be well distributed over the Coastal Plain
in our territory. This and the preceding species are listed under the
genus Triadenum. by Small.

3. //. adpressum Bart. — Various provinces, Georgia north and west
to beyond the limits of our territory.

4. //. cistifolium Lam.— Sometimes found at the margins of acid
swamps and ponds. Coastal Plain, F'lcjrida north to South Carolina
and west to beyond the limits of our territory. This is given as
H. opacura T. & G. by Small.

5. H. myrtifolium Lam. St. John's-wort — Acid ponds, Coastal
Plain, Florida north to South Carolina and west to Mississippi.

124 PUBLIC HEALTH BULLETIN NO. 286

6. H. galioides Lam. — Very common in acid ponds ranging over
most of om- Coastal Plain territory. Some observers hav^e noted that
there is rarely an association of Anopheles quadrimaculatus with this
plant. This species includes H. fasciculatum Lam. of Small's Manual.

7. H. densiflorum Pursh — Sometimes difficult to distinguish from
the preceding and like it found in acid situations. Its range includes
most of our area.

THEACEAE CameUia family

1. Gordonia Ellis.

6. lasianthus (L.) Ellis. Red Bay — Non-alluvial acid swamps and
bays, Coastal Plain, Florida north to North Carolina and west to the
limit of our territory.

LAURACEAE Laurel family

1. Persea Gaertn.

P. pubescens (Pursh) Sarg. Sweet Bay — Non-alluvial swamps,
Coastal Plain, Florida north and west to the limits of our territory.
It is listed under the genus Tamala by Small.

2. Glabraria L.

G. geniculata (Walt.) Britton — Rare plant, found around ponds,

mostly in acid situations. Coastal Plain, Florida to and beyond the

limits of our territory.

3. Benzoin Fabr.

1. Leaves tapering to the base; petioles slender and long 1. B. aestivale.

1. Leaves rounded or cordate at the base; petioles stout 2. B. melissaefolium.
and rather short.

1. B. aestivale (L). Nees. Spice-bush — Wet woods and swamps,
various provinces over all of our territory,

2. B. melissaefolium (Walt.) Nees — Uncommon in swamps and
pond margins over all of our Coastal Plain territory.

MELASTOMACEAE Meadow Beauty family

1. Rhexia L.

1. Neck of the mature calyx tube as long as the body or 2.

longer.

1. Neck of the mature calyx tube much shorter than the 3.
body.

2. Leaf-blades narrowly linear 1. R. cubensis.

2. Leaf -blades elliptic or lanceolate 2. R. mariana.

3. Stems and branches round or nearly so 3. R. lanceolata.

3. Stems and branches sharply angled or 4-winged 4.

4, Flowers over 2 cm. across, colored 5.

4. Flowers less than 2 cm. across, white 6. R. parviflora.

5. Lobes of calyx longer than neck of calyx tube; leaves 5. R. aristosa.
entire or nearly so.

A GUIDE AND KEY TO AQUATIC PLANTS 125

5. Sepals shorter than neck of calyx tube or about as long; 6.
leaves toothed.

6. Plant tuberous rooted 6. R. virginicat

6. Plant not tuberous rooted 7. R. stricta.

1. R. cubensis Griseb.— Swamps, Coastal Plain, Florida to Georgia
and Mississippi.

2. R. mariana L. Aleadow Beauty — Various situations over all of
our range. As treated here it includes R. nashii Small.

3. R. lanceolata Walt. — Small species occurring in the Coastal Plain,
Florida north and west to the limits of om- territory.

4. R. parviflora Chapm. — Known to occur only in shallow ponds
near Apalachicola, Florida, although the senior writer collected speci-
mens which might be referred to this species from a limesink in South-
west Georgia.

5. R. aristosa Britton— Phieland swamps. Coastal Plain, Georgia
north to beyond the limit of our range.

6. R. virginica L. — Wet situations over all of our range.

7. R. stricta Pursh — Coastal Plain species, supposed to range from
Georgia to North Carolina and Mississippi.

LYTHRACEAE Loosestrife family

1. Didiplis Raf.

D. diandra (Nutt.) Wood. Water Purslane — Infrequent but range
includes all of our area.

2. Ammannia L.

1. Petals present 2.

1. Petals wanting 1. A. latijolia.

2. Style long and slender 2. A. coccinea.

2. Style verj' short and stout 3. A. teres.

1. A. latijolia L. — Limesinks and swamps. South Florida and the
Florida Keys.

2. A. coccinea Rottb. — Range includes all of our territory, but most
frequent iji non-acid regions.

3. A. teres Raf. — Florida north to beyond the limit of our region.
Supposed to differ from A. latijolia only in having a corolla. The
senior writer has seen it onh' near the coast.

3. Rotala L.

R. ramosior (L.) Koehnt — Ranges over all our territorj^, seeming
to prefer non-acid situations.

4. Decodon J. F. Gmel.

D. verticillatus (L.) Ell. Water Willow — Fairly frequent over all
of our territory. wShows an extremely wide range of acidity tolerance
as it is found in the very acid Okefinokee Swamp and the neutral
Reelfoot Lake alike.

126 PUBLIC HEALTH BULLETIN NO. 286

5. Lythrum L.

1. Stem creeping; leaves mostly opposite 1. L. flagellar e.

I. Stem erect; leaves mostly alternate 2.

2. Leaf-blades rounded or cordate at base 2. L. alatum.

2. I>eaf-blades narrowed at the base 3.

3. Leaf-blades thick, numerous, and less than 1.5 cm. long 3. L. lanceolatum.

on branches.
3. Leaf-blades thin, few, and over L5 cm. long on branches. 4. L. curlissii.

1. L. Uagellare Shuttlw. — Swamps in lower peninsular Florida.

2. L. alatum Pursh — Swamps in various provinces over all of our
territory except perhaps Florida.

3. L. lanceolatum Ell. — Coastal Plain, Florida north to South
Carolina and west to beyond the limit of our area, mostly in alluvial
situations.

4. L. curtissii Fernald — Known only from muddy and often
calcareous swamps, North Florida and the immediately adjacent
portion of South Georgia.

ONAGRACEAE Evenmg primrose family

1. Ludwigia L

1. Leaves opposite 2.

1. Leaves alternate 4.

2. Flowers sessile; corolla inconspicuous 3.

2. Flowers with long stalks; corolla conspic- 1. L. arcuata.
uous.

3. Calyx tube usually bearing one or more long bracts 2. L. natans.
above base; calyx tube without 4 longitudinal green
bands.

3. Bract, when present, borne basally; calyx tube with 3. L. paluslris.
4 longitudinal green bands.

4. Flowers showy, stalked 4. L. alternifolia.

4. Flowers mostly not showy, sessile 5.

5. Petals wanting or minute 6.

5. Petals as long as the sepals or longer, showy 15.

6. Capsule 1-3 mm. long, plants sometimes de- 7.
pressed.

6. Capsule 3-8 mm. long, plants erect 8.

7. Plant depressed; leaves entire 5. L. microcarpa.

7. Plant ascending; leaves toothed near the apex 6. L. curtissii.

8. Capsule about as thick as long, not cylindric. 9.

8. Capsule much longer than thick, cjlindric..- 7. L. glandulosa.

9. Foliage and fruit copiously pubescent 8. L. pilosa.

9. Foliage and fruit glabrous or nearly so 10.

10. Inflorescence terminal 9. L. suffruticosa.

10. Flowers distributed over plant 11.

II. Capsules turbinate or obpyramidal but not globular.. 12.

11. Capsule globular 10. L. sphaerocarpa.

12. Capsule with the angles rounded or merely 13.

square.

12. Capsule with Ihe angles winged or at least 14.
margined.

A GUIDE AND KEY TO AQUATIC PLANTS 127

13. Capsule glabrous, the angles rounded; with two bracts 11. L. polycarpa.

adnate to the calj'x tube near base.
13. Capsule puberulent, the angles square; bracts not 12. L. simulata.
adnate to the calyx tube.

14. Sepals not quite as broad as long, almost as 13. L. alaia.

long as the capsule.
14. Sepals broader than long, only about one-half li. L. lanceolata.
as long as the capsule.

15. Capsule round, cylindric 15. L. linijolia.

15. Capsule narrowly obpyramidal, tapered from base to 16. L. linearis.
apex.

1. L. arcuata Walt. — This species is cited by Small as Ludvngiantha
arcuata (WaH.) Small. Occurs in marshes and ponds, Coastal Plain,
Florida to Virginia, often in very acid situations.

2. L. natans Ell. — This species exists in our territory in two varieties
and includes both Isnardia repens and Isnardia intermedia of Small.
It is a Coastal Plain species and is found from Florida north and west
to the limits of our territory.

3. L. palustris (L.) Ell. — Also present in our territory in two
varieties. More widespread than the preceding and not limited to
the Coastal Plain. Range includes all of our territory. It is found
over a wide range of acidity. Anopheles quadrimaculatus is often
found associated with it. This plant is given under the genus
Isnardia in Small. A related species of Ludwigia, L. spathulata T. &
G., which is a hairy species with the capsule turgid and constricted at
the top, is found in ponds in Middle Florida.

4. L. alterni-folia L. — Low places over all of our territory.

5. L. microcarpa Michx. — Coastal Plain, Florida to North Carolina
and Mississippi, seeming to prefer non-acid conditions.

6. L. curtissii Chapm. — Related to the preceding, but found only
on the peninsula of Florida.

7. L. glandulosa Walt. — Coastal Plain and occasionally in other
provinces, most frequently in alluvial areas along rivers. Range
includes all of our territory.

8. L. pilosa Walt. — Hairy species, most often found in acid ponds
and bays, Coastal Plain, Florida to North Carolina and beyond our
limit in Louisiana.

9. L. suffruticosa Walt. — Margins of acid ponds. Coastal Plain,
Florida to North Carolina.

10. L. sphaerocarpa Ell. — Frequent species over all of our Coastal
Plain. Commonly observed by the senior author m acid, open
limesinks in Georgia.

11. L. polycarpa Short & Peter — Not observed in our territory by
the writers, but said to be present in Tennessee. Has been seen in
aquatic areas along the Mississippi not far north of our areas.

128 PUBLIC HEALTH BULLETIN NO. 286

12. L. simulata Small — Coastal Plain swamps, Florida to North
Carolina.

13. L. alata Ell. — Coastal Plain, Florida north and west to and
beyond the limits of our territory.

14. L. lanceolata Ell. — Coastal Plain aquatic areas, Florida to
North Carolina.

15. L. limjolia Poir. — Acid pineland swamps, Coastal Plain,
Florida to North Carolina and Mississippi.

16. L. linearis Walt. — Acid places, Coastal Plain, Florida north
and west to beyond the limits of our territory.

2. Jussiaea L.

1. Plants creeping or floating 2.

1. Plants erect 3.

2. Leaf-blades long-pet ioled; flowers 2-3 cm. 1. J. dij[jusa.

across.
2. Leaf-blades short-petioled; flowers 3-4 cm. 2, ./. grandijlora.

across.

3. Capsule long, narrowly cylindric, more than 3 cm. long. 4.
3. Capsule shorter, obconic or nearly cylindric, less than 6.
2 cm. long.

4. Calyx of 5 sepals 3. J. leptocarpa.

4. Calyx of 4 sepals 5,

5. Leaf-blades very narrow 4. J. angustifolia.

5. Leaf-blades broad 5. J. scabra.

6. Fruit winged; leaf-blades sessile and deciirrent 6. J. decurrens.
onto stem.

6. Fruit not winged; leaf-blades short petioled 7. J. peruviana.

1. J. dijfusa Forsk. — Florida westward, mostly in the Coastal
Plain, to beyond our limits. Not common in the eastern part of our
territory.

2. J. grandiHora Alichx. — Ranges over all of our Coastal Plain,
and is established in some localities northward. Most often found in
aquatic areas associated with streams, and often grows well in im-
poundments. It and the preceding have been found in association
with Anopheles quadrimaculatus.

3. J. leptocarpa Nutt.— Partial to acid places. Coastal Plain,
Florida to Georgia and westward to beyond the limits of our territory.

4. J. angustifolia Lam. — Southernmost part of our territor}^,
Florida to beyond our western limit, in swamps.

5. J. scabra Willd. — Wet places in Florida.

G. J. decurrens (Walt.) DC. — Ranges over all of our area in low
grounds, most frequent in the Coastal Plain. Often found in weedy
habitats.

7. J. peruviana L. — Everglades and in swamps, peninsular Florida.

A GUIDE AND KEY TO AQUATIC PLANTS 129

HALORAGIDACEAE Water milfoil family

1. Proserpinaca L.

1. Leaves all nearly alike and all deeply lobed or divided-- 2.

1. Upper leaves (those bearing flowers in axils) toothed 1. P. palustria.
but not lobed or divided.

2. Rachis of leaves about as broad as the segments- 2. P. pectinata.

2. Rachis of leaves much broader than the seg- 3. P. intermedia.
ments or lobes.

1. P. palustris L. Mermaid Weed — This species is found Ln our
region in several varieties, and it includes not only P. palustris but
also P. amhlygona and P. platycarpa of Small's Manual. The range
of the species covers all of our territory, and it is often found in acid
situations but shows some tolerance.

2. P. pectinata Lam. — ^Ranges over all of our area, but most com-
mon in the Coastal Plain. Found in the same type places as the
preceding species.

3. P. intermedia Mackenzie — Possibly a hybrid between the two
preceding. Rare but known from Georgia north to beyond the
limit of our territory.

2. Myriophyllum L.

1. Emersed leaves nearly like submerged leaves 1. M. braailiense.

1. Emersed leaves definitely different from submerged 2.
leaves.

2. Stamens 4; corolla persistent 3.

2. Stamens 8; corolla deciduous 2. M.laxum.

3w Floral (emersed) leaves with ovate, toothed blades 3. M. heterophyllum.

3. Floral leaves deeplj- lobed or divided 4. M. pinnalum.

1. M. brasiliense Cambess. Parrot 's-feather — Tropical species,
introduced in the Coastal Plain, Florida to Georgia and westward
beyond the limits of our territory. It is often found in association
with Anopheles quadrimaculatus and seems to prefer neutral or alkaline
waters. This species is listed under M. proserpinacoides Gill by Small,

2. M. laxum Shuttlw.- — Rare species, found onlj^ ia ponds and lakes
in North Florida, South Georgia and South Alabama. The senior
writer has collected it from acid, open limesinks in Southwest Georgia.

3. Af. heferophyllum Miclix. — Ranges over all of our territory, but
most common in the Coastal Plain. Seems to prefer less acid waters
than the following. Anopheles quadrimaculatus is often found associ-
ated witli it.

4. M. pinnatum (Walt.) B. S. P. — Should range over all of our terri-
tory. It is the impression of the writers that this species is found in
more acid waters than the preceding, but owing to the difficulty of
identifying the Myriophyllum. group in the field this impression may be
erroneous. It is most common in the Coastal Plain.

130 PUBLIC HEALTH BULLETIN NO. 286

CORNACEAE Dogwood family
1, Nyssa L.

1. Fruits solitary, large (3-4 cm. long); stone winged or 2.

sharply ridged.
1. Fruits 2 or more together, small (1-1.5 cm. long) ; stone 1. A^. sylvatica.
not winged or sharply ridged.

2. Fruit purple or blue, stone only sharp-ridged; 2. A^. aquatica.

large straight tree with swollen base,
2. Fruit red, stone winged ; small crooked tree 3. N. ogeche.

1. N. sylvatica Marsh. Black-gum— Present in our region in no less
than four varieties but variety bijlora (Walt.) Sarg. is the most char-
acteristically aquatic. Ranges in the Coastal Plain (and occasionally
in upland provinces) over most of our territory and, in acid regions at
least, is very common. N. ursina Small is a copiously branched
shrubby species with a globular drupe which is known only from pine-
land swamps in the Apalachicola River delta in Florida. Our com-
mon aquatic Black-gum is listed as N. biflora Walt, by Small.

2. N. aquatica L. Tupelo-gum^ — Ranges over all of our Coastal
Plain territory, being seen most often in alluvial situations.

3. N. ogeche Marsh. Ogeche Lime — Acid situations from around
Apalachicola in Florida to extreme southern South Carolina. It has
a shrubby variety, var. acuminata (Small) Eyles, in pineland swamps
near the coast in Georgia.

UMBELLIFERAE Carrot family

1. Eryngium [Tourn.] L.

E. aquaticum L. Snakeroot — Moist places along the coast from

Florida north.

2. Hydrocotyle [Tourn.] L.

1. Leaves peltate 2.

1. .Leaves not peltate 3.

2. Fruit notched at the base and the apex 1. H. umhellata.

2. Fruit not notched 2. H. verticillata.

3. Leaves shallowly lobed; flower clusters almost without 3. H. americana.

stalks.
3. Leaves deeply lobed; flower clusters with long stalks 4. H: ranunculoides.

1. H. umhellata L. Water Penny wort —Coinmon aquatic species
and occurs over all of our area, especially in the Coastal Plain.
Found in a wide variety of conditions.

2. H. verticillata Thunb. —Should also be found over all of our
area but not as commonly as the preceding. Most common in the
Coastal Plain.

A GUIDE AND KEY TO AQUATIC PLANTS 131

3. H. americana L. — Present in our area in North Carolina and
Tennessee.

4. H. ranunculoides L. f.— Range includes all of our area. The
senior writer has observed it in alkaline waters near the coast.

3. Centella L.

C. erecta (L. f.) Femald —Shallow ponds and low places, Coastal
Plain, Florida north and west to beyond the limits of our territory.
Small's Manual gives this as C. repanda (Pers.) Small.

4. Cicuta L.

1. Fruit grooved at the junction of the carpels 1. C. curtissii.

1. Fruit not grooved at the junction of the carpels 2. C. maculata.

1. C. curtissii Coult. & Rose— Swamps in the Coastal Plain,
Florida north and west to beyond the limits of our territory.

2. C. maculata L. — Swamps, mostly in the western part of our
territory.

5. Sium [Tourn.] L.

5. suave Walt. — Uncommon in ponds, marshes, and swamps over
most of our area. Small lists this as S. cicutaefolium Schrank.

6. Ptilimnium Raf.

1. Leaves simple, round 1

1. Leaves compound, with narrowly linear segments.

2. Fruit 2 mm. long or more; if only 2 mm. long

sepals deltoid.
2. Fruit 1.5 mm. long or less; sepals lanceolate to
subulate.

3. Sepals deltoid; fruit about 2 mm. long

3. Sepals lanceolate to subulate; fruit 3-4 mm. long

1. P. nodosum (Rose) Mathias — KJnown only from ponds on the
Coastal Plain, Southwest Georgia.

2. P. nuttallii (DC.) Britton — Swamps in our region from Alabama
westward.

3. P. capillaceum (Michx.) Raf. — Published range includes all of
our area, but probably most common in w^et areas along the coast.

4. P. costatum (EU.) Coult. & Rose — Coastal Plain swamps, Georgia
to North Carolina.

7. Oxypolis Raf.

0. filijormis (Walt.) Britton — Acid low pinelands and shallow ponds
and swamps. Coastal Plain, Florida to South Carolina and westward
to beyond the limits of our range.

1.

P.

nodosum.

2.

2.

2.

P.

nuttallii.

3.

P.

capillaceum.

4.

P.

cofitaium.

132 PUBLIC HEALTH BULLETIN NO. 286

CLETHRACEAE White alder family

1. Clethra [Gronov.] L.

1. Leaf-blades glabrous beneath or nearh' so 1. C. alnifolia.

1. Leaf-blades densely hairy or wooly beneath 2. C. lomentosa.

1. C. alnifolia L. Sweet Peppcrbush — Swamps, mostly acid,
Florida north and west to beyond the confines of our area.

2. C. tomentosa Lam. — Similar situations to the preceding, but dis-
tribution more restricted. Found from North Florida to North
Carolina and Alabama in the Coastal Plain.

ERICACEAE Heath family

1. Leucothoe D. Don

1. Flower clusters axillary 1. L. acnminata.

1. Flower clusters terminal 2. L. raccmosa.

1. L. acuminata (Ait.) D. Don, Fetter-bush — Acid swamps and
ponds, Coastal Plain, Florida to South Carolina. The related L.
axillaris (Lam.) D. Don may perhaps occasionally be found in aquatic
situations.

2. L. racemosa (L.) A. Gray- -Found in two varieties in acid swamps
and ponds, Coastal Plain, Florida north ar^d west to beyond the
boundaries of our territory. The treatment here includes Eubotrys
racemosa (L.) Nutt. and E. elongata Small of Small's Manual of the
Southeastern Flora.

2. Ampelothamnus Small

A. phyllyreifolius (Hook.) Small — Found usually climbing on
cypress in acid ponds and swamps. Coastal Plain, North Florida to
Alabama and Georgia in the Coastal Plain.

3. Desmothamnus Small

D. lucidus (Lam.) Small — Common slirub of acid swamps, ponds,
and bays; Coastal Plain, Florida. north and west to beyond the limits
of our territory.

PRIMULACEAE Primrose family

]. Hottonia L.

H. inflata Ell. Featherfoil— Published range includes all of our
Coastal Plain, but rare. Seems to be most common in the neutral
waters of aquatic areas in the Mississippi Valley.

2. Samolus [Tourn.] L.

S. 'pauciflorus Raf. Water Pimpernel — ^Wet places, usually not
acid, over all of our temtoiy.

A GUIDE AND KEY TO AQUATIC PLANTS 133

OLEACEAE Olive famUy

1. Fraxinus [Toiirn.] L.

1. Twigs pubescent; fruit not as below 1. F. profunda.

1. Twigs glabrous or, if pubescent, the body of the fruit 2.
broadly winged to base.

2. Leaflets usually. 5, thick and leathery 2. F. pauci flora.

2. Leaflets usually 7, not so thick nor leathery 3. F. caroliniana.

1. F. 'profunda Bush — Swamps, Georgia to Alabama and north-
ward.

2. F. pavciflora Nutt. Water Ash — Swamps in the lower Coastal
Plain, Florida to Georgia and west to the limit of our territory.

3. F. caroliniana Mill. Water Ash — Swamps, over all of our

Coastal Plain.

2. Forestiera Poir.

F. acuminata (Michx.) Poir. Swamp Privet — Most frequently in
river swamps, over all but the northeastern portion of our territory.

LOGANIACEAE Logania family

1. Cynoctonum J. F. Gmel.

C. mitreola (L.) Britton — Occasionally aquatic, found mostly in
the Coastal Plain, Florida north and west to beyond the limits of
our range.

GENTIANACEAE Gentian family

1. Sabatia Adans.

1. Petals usually 4 or 5 2.

1. Petals usually 8-12 3.

2. Sepals foliaceous, broadened near end L S. calycina.

2. Sepals not foliaceous, elliptic 2. S. campanulata.

3. Petals less than 2.5 cm. long, usually acutish at tip 4.

3. Petals more than 2.5 cm. long, usually rounded at tip.. 3. S. dacandra.

4. Sepals much shorter than corolla 4. S. harperi.

4. Sepals as long as corolla or nearly so 5. S. foliosa.

1. S. calycina (Lam.) Heller — Alluvial situations over all of our
Coastal Plain.

2. S. campanulata (L.) Torr. — Range includes all of our territory.
Most common in acid moist places in the Coastal Plain, sometimes in
ponds.

3. S. decandra (Walt.) Harper — Cypress and perhaps other ponds,
Coastal Plain, Florida to Alabama and South Carolina.

4. S. harperi Small — Acid swamps and along pond-margins, Coastal
Plain, Florida to Alabama and South Carolina.

5. S. joliosa Fernald^ — Coastal Plain in Florida and Alabama.

134 PUBLIC HEALTH BULLETIN NO. 286

MENYANTTTACEAE Bogbean family

1. Nymphoides [Tourn.] Hill

1. Leaf-blades thick, pitted beneath; petiole purple-gland- 1. N. aquaticum.

ular.
1. Leaf-blades thin, not pitted beneath; petiole slender 2. N. cordatum,

and smooth.

1. N. aquaticum (Walt.) Kuntze. Floating-heart — Range includes
all of our Coastal Plain. Most often seen in rather acid and often
open ponds.

2. N. cordatum (Ell.) Fernald — Less common than the preceding in
most of our territory, but found in similar situations and with roughly
the same range. A'^. lacunosum (Vent.) Kuntze is the name given this
species in Small's Manual.

CONVOLVULACEAE Mommg glory family
1. Breweria R. Brown

B. aquatica (Walt.) A. Gray — Found infrequently around shallow
ponds. Range includes all of our Coastal Plain.

HYDROPHYLLACEAE Waterleaf family

L Hydrolea L.

1. Flowers in terminal clusters; styles several times as 2.

long as ovary, pubescent at base; filaments as long

or nearly as long as corolla.

1. Flowers in axillary clusters; styles slightly longer than 3.

ovary, glabrous; filaments much shorter than corolla.

2. Leaf-blades ovate to elliptic; calyx lobes less 1. H. ovata.

than 7 mm. long; flowers paniculate.
2. Leaf-blades elliptic to elliptic-lanceolate; calyx 2. H. corymbosa.
lobes over 7 mm. long; flowers corymbose.

3. Stjpal.s linear or linear-lanceolate; stem villous above 3. H. quadrivalvis.

3. Sepals ovate-lanceolate; stem nearly glabrous above 4. H. affinis.

1. H. ovata Nutt. — Ponds and swamps, Coastal Plain, Georgia
north and west to beyond the limits of our territory.

2. H. coryinbosa Macbride— -Limited in distribution, Coastal Plain,
Florida to South Carolina, mostly in calcareous swamps.

3. H. quadrivalvis Walt.— Probably the most frequent species of
the genus in om- territory. Range includes all of our Coastal Plain,
often in acid places.

4. H. affinis A. Gray — Swampy places, but in our territory only in.
its western part in Mississippi.

VERBENACEAE Verbena family
1. Lippia [Houston] L.

L. lanceolata Michx. Frog-fruit — Found mostly in alluvial situa-
tions, over most of our area. L. nodiflora (L.) Michx., a creeping

A GUIDE AND KEY TO AQUATIC PLANTS 135

species, is found in moist places in various parts of our territory,
but is not truly aquatic. Small lists these species under the genus
Phyla.

LABIATAE Mint family

1. Scutellaria L.

S. laterifolia L. Skullcap —Found over all of our area, apparently
most common in alluvial situations.

2. Lycopus [Tourn.] L.

1. Blades of the lower leaves divided or deeply lobed 1. L. americanus.

1. Blades of the lower leaves merely toothed 2.

2. Leaf-blades petioled 2. L. rubellus.

2. Leaf-blades sessile and sometimes clasping 3.

3. Stems glabrous at least on the lower part; bracts sub- 3. L. sessilifolius.

tending flower clusters narrowed to base.
3. Stems densely puberulent or finely pubescent; bracts 4. L. pubens.
truncate at base.

1. L. americanus Muhl. — Wet places over all of our territory.

2. L. rubellus Moench— Coastal Plain in various situations includ-
ing river swamps, Florida north and west to beyond the confines of
our area.

3. X. sessilifolius A. Gray— Distribution almost the same as that
of the preceding.

4. L. pubens Britton — Coastal Plain in acid pineland ponds,
Florida to Mississippi and South Carolina.

SCROPHULARIACEAE Figwort family
1. Herpestris Gaertn. f.

H. rotundifolia Gaertn. f. — Ponds near the coast, Florida to be-
yond our limit m the north. Not restricted to tidal habitats as has

been supposed.

2. Hydrotrida Small

H. caroliniana (Walt.) Small— Range includes all of our Coastal
Plain. Not frequently recorded from some areas, but in Georgia it
is common in limesink ponds in the Southern part of the State and
has been noted a few times along the coast.

3. Gratiola L.

1. Leaves elliptic-lanceolate to ovate; capsule equalling 1. G. virginiana.

or exceeding sepals.
1. Leaves linear-lanceolate; capsule exceeded by sepals — ?. G. ramosa.

1. G. virginiana L. Hedge Hyssop — Range includes all of our terri-
tory, and is occasionally found in truly aquatic areas especially in
alluvial situations.

136 PUBLIC HEALTH BULLETIN NO. 2 86

2. G. ramosa Walt. — Coastal Plain, Florida north and west to
teyond the limits of our temtory. Found in aquatic situations
mostly in acid pin eland swamps or pools.

4. Micranthemum Michx.

M. umbrosum (Walt.) Blake— Shallow ponds, often acid, Florida to
North Carolina and west to beyond our limits in the Coastal Plain.

5. Mimulus L.

1. Leaves not petioled; stem not winged 1. M. ringens.

1. Leaves petioled; stem 4-winged 2. M.alatus.

1. M. ringens L. Monlvcy-flower — Range includes all of our states,
occurring mostly along streams. Rare in the Coastal Plain.

2. M. alaius Ait. — The remarks concerning the preceding can also
be applied to this.

ACANTHACEAE Acanthus family
1. Hygrophila R. Brown

H. lacustris (Schlecht.) Nees — Lower Coastal Plain, Florida west-
ward but has its best development in the lower Mississippi delta
marshes.

2. Justicia L.

1. Corolla 2-2.5 cm. long 1. J. crassifolia.

I. Corolla about 1 cm. long 2.

2. Flowers in head-like spikes 3.

2. Flowers scattered along one side of the upper 4.
I)art of stalk.

3. Leaves linear, mostly shorter than peduncle 2. J. americana.

3. Leaves elliptic, mostly longer than peduncle 3. J. humilis.

4. Leaves remote, reflexed; corolla-tube 5-6 mm. 4. J. angusta.

long.
4. Leaves not remote or reflexed; corolla-tube 8-10 5. J. lanceolata.
mm. long.

1. J. crassifolia Chapm. — Kno\vn only from swamps on the Coastal
Plain in Florida.

2. J. americana (L.) Vahl — Georgia north and west to beyond the
limits of our territory. Most common along rivers, and in the Tennes-
see Valley is often found in association with the production of Anoph-
eles quadrimaculatus. This species is listed by Small under the genus
Dianihera.

3. J. humilis Michx. — Swamps, Coastal Plain, Florida north and
west to beyond the limits of oiu* territory, often in alluvial situations.
This species is called J. ovata Walt, by Small.

4. J. angusta (Chapm.) Small — Known only from pineland ponds
in Florida.

5. J, lanceolata (Chapm.) Small — Swamps on the Coastal Plain,
Florida north and west to beyond the boundaries of our area.

A GUIDE AND KEY TO AQUATIC PLANTS 137

LENTIBULARIACEAE Bladderwort family

1. Utricularia L.

1 . Stems erect from base, definitely anchored in substra- 2.

tum; leaves and bladders rarely seen.

1. Stems mostly drifting free in water; leaves dissected 3.
and bladder bearing.

2. Flowers yellow 1. U. cornuia.

2. Flowers purple 2. U. resupinata.

3. Flowers purple ^ 3. U. -purpurea.

3. Flowers yellow 4.

4. Scape with a conspicuous whorl of inflated 4. U. inflata.
floats at base.

4. Scape without a whorl of floats 5.

5. Scape usually with 5-25 flowers, stout, over 10 cm. high, 6.

5. Scape usually with 1-2 flowers, slender, less than 10 cm. 8.
high.

6. Leaves forked and each fork 2-3 times divided; 7.

flowers 12-15 mm. broad.

6. Leaves forked and each fork 4-5 times dissected; 5. U. foliosa.
flowers 15-20 mm. Vjroad.

7. Pedicels recurved at maturity; scapes erect 6. U. vulgaris.

7. Pedicels straight at maturity; scapes flexuous 7. U. floridana.

8. Spur equalling or longer than lower lip of corolla. 9.

8. Spur shorter than lower lip of corolla 8. U. gibba.

9. Spur tapering from base to apex; all leaves bladder- 9. U. biflora.

bearing.

9. Spur conic below and linear near tip; some leaves with- 10. U. fibrosa.
out bladders.

1. U. cornuta Michx. — As considered here this species includes
Stomoisia cornuta (Michx.) Raf. and S. juncea (Vahl.) Barnh. as cited
by Small. The species is primarily of Coastal Plain distribution,
although it is knoAvn from other provinces, and its range includes all of
our territory. It is ordinarily found in acid places. A local species,
U. virgatula Bamh., occurs also in our territory. It may be distin-
guished by its very short corolla which is scarcely longer than the calyx.

2. U. resvpinata B. D. Greene — Shallow water, Florida north to
beyond the limits of our territory. Small gives this species as Lecticula
resupinata (B. D. Greene) Bamh.

3. U. purpurea Walt. — Ponds and lakes of varying acidity, its range
covering all of our territory. It is listed by Small as Vesiculina pur-
purea (Walt.) Raf. Anopheles quadrimaculatus breeding has been found
associated with this and other plants of this genus.

4. JJ. infiaia Walt.^ — Coastal Plain over all of our territory, in ponds
with wide range of acidity. There is a smaller variety distinguished
by Small as JJ. radiaia Small.

5. U. foliosa L. — Large flowered species, lower Coastal Plain,
Florida westwaid along the Gulf of Mexico to beyond the limits of
our territory.

138 PUBLIC HEALTH BULLETIN NO. 286

6. U. vulgaris L. — This species is cited by Small as U. macrorhiza
LeConte. Present in our territory only in the northern part. Prob-
ably occurs in North Carolina and has been collected in Northwest
Tennessee.

7. U. fioridana Nash — Ponds on the Coastal Plain in Florida and
Georgia.

8. TJ. gibba L. — Ranges over all of our area, but probably most
common in shallow water of the Coastal Plain.

9. U. biflora Lam. — This species is given as TJ. pumila Walt, by
Small. Coastal Plain, Florida north and west to beyond the limits
of our territory.

10. U. fibrosa Walt. — Pineland ponds, Coastal Plain, Florida to
Mississippi and north to beyond the limits of our territory.

RUBIACEAE Madder family
1. Pinckneya Michx.

P. pubens Michx. Georgia Feverbark — Sandy, acid swamps,

Middle Florida to the extreme southern part of South Carolina in

the Coastal Plain.

2. Cephalanthiis L.

C. occidfnialis L. Buttonbush — Commonest aquatic shrub and is
very often found in ponds supporting the breeding of Anopheles quad-
rimaculatus . Shows the widest degree of acidity tolerance, being
found in the extremely acid Okefinokee Swamp and neutral or
even alkaline limesinks and alluvial swamps. Range covers all of
our territory.

CAPRIFOLIACEAE Honeysuckle family

1. Sambucus [Tourn.] L.

1. Lateral leaflets merely toothed 1. S. canadensis.

1. Lateral leaflets 2-3 times divided, especially the lower 2. S. simpsonii.
pair.

1. /S. canadensis L. Elder— Moist places over all our range except
possibly in Florida.

2. S. simpsonii Rehder. Gulf Elder — Lower Coastal Plain, Florida
to Louisiana, in marshes and hammocks.

CAMPANULACEAE BeU-flower family
1. Campanula [Tourn.] L.

C. fioridana S. Wats. — Grassy swamps and marshes. East Florida
and the peninsula.

A GUIDE AND KEY TO AQUATIC PLANTS 139

COMPOSITAE Composite family

1. Sclerolepis Cass.

S. unifiora (Walt.) B. S. P. — Pineland and cypress ponds, Coastal
Plain, Florida to Alabama* and north to beyond the limits of our
territory.

2. Eupatorium L.

1. Flowers purple 1. E. coelestinum.

1. Flowers white 2.

2. Leaf-blades narrowed at the base 3.

2. Leaf-blades broadened at the base 2. E. rotundifolium.

3. Bracts of the involucre acute or acuminate; leaves re- 3. E. leucolepis.

motely toothed or nearly entire.

3. Bracts of the involucre obtusish; leaves sharply toothed_ 4. E. semiserratum.

1. E. coelestinum L. Mist-flower — Includes all of our area. Marshes
and along pond margins often in alluvial situations.

2. E. roiundifolium L. — The range of this species in all of its varie-
ties covers all of our area, but it is commonest on the Coastal Plain.
It is often non-aquatic but is occasionally found in swamps. As used
here E. roiundijolinm includes also E. verbena ejolium, E. puhesccns,
and E. scah^dum of Small's Manual

3. E. leucolepis (DC.) T. & G.— Ranges over all of our Coastal
Plain in acid ponds or bogs.

4. E. semiserratum DC. — Swamps and ponds in the Coastal Plain,
Florida north and west to beyond the limits of our territory.

3. Mikania Wmd.

M. scandens (L.) Willd. Hemp-weed — Swamps, mostly alluvial,
over all of our territory.

4. Pluchea Cass.

1. Plants perennial 2.

1. Plants annual 3.

2. Outer bracts of involucre acuminate.* 1. P. foetida.

2. Outer bracts of involucre obtuse or merely acute. 2. P. imbncata.

3. Leaves not decurrent on stem making it winged 3. P. petiolata.

3. Leaves decurrent on stem making it winged 4. P. quitoc.

1. P.joetida (L.) DC. — Ponds, mostly in the Coastal Plain, Florida
north and west to beyond the limits of our territory.

2. P. imbricata (Kearney) Nash — Swamps and ponds. Coastal
Plain, Florida to South Carolina.

3. P. petiolata Cass. — Most often found in alluvial situations, its
range covering all of our territory.

4. P. quitoc DC. — Naturalized species, known in this country from
marshy places in West Florida.

140 PUBLIC HEALTH BULLETIN NO. 2 86

5. Coreopsis L.

C. nudata Nutt. — Pink-flowered species found in acid ponds and
wet pinelands, lower Coastal Plain, Georgia and Florida.

6. Bidens L.

1. Flowers inconspicuous (ray-flowers wanting) 2.

1 . Flowers conspicuous, yellow 3.

2. Achene long-awned, awns barbed downward 1. B. frondosa.

2. Achene short-awned, awns barbed upward 2. B. dtscoidea.

3. Leaf-blades simple 4.

3. Leaf-blades compound 6.

4. Achene straight, flat, not strongly keeled, and 3. B. laevis.
without pale corky margins; rays 1.&-3 cm.
long.
4. Achene curved, strongly keeled, and with pale 4. B. cernua.
corky margins; rays not over L7 cm.

6. Achene 6-8 mm. long, ciliate 5. B. coronata.

5. Achene 2-4 mm. long, not ciliate 6. B. milis.

1. B. Jrondosa L. — Damp soil, often as a weed, over most of our
area.

2. B. discoidea (T. & G.) Britton — Georgia westward and northward
to beyond the limits of our area, in swamps and around pond margins.

3. B. laevis (L.) B. S. P. — Range similar to the preceding, but more
common in the Coastal Plain. Found in swani{:s and low woods.

4. B. cernua L. — Found mostly north of our territory, but recorded
from wet places in North Carolina, Georgia, and Tennessee.

5. B. coronata (L.) Britton — Swamps, ranging over all of our
territory.

6. B. mitis (Michx.) Sherff — Coastal Plain, Florida west to Mis-
sissippi and north to beyond the limits of our territory.

PRINCIPAL WORKS CONSULTED IN COMPILATION OF GUIDE

Britton, N. L. and Addison Brown.

1913. AN ILLUSIRATED FLORA OF IHE NORTHERN UNITED STATER, CANADA

AND THE BRITISH POSSESSIONS, ed. 2. Scribuer.
CoKBR, W. C. and H. R. Totten.

1937. TREES OF THE SOUTHEASTERN STATES. University of North Carolina
Press, Chapel Hill.
Fassett, N. C,

1940. A MANUAL OF AQUATIC PLANTS. McGraw-Hill, Ncw York.
Hitchcock, A. S.

193.5. MANUAL OF THF GRASSES OF THE UNITED STATES. U. S. Department
of Agriculture, Miscellaneous Publication No. 200.
Robinson, B. L. and AL L. Fernald, ed.

1908. Gray's nfw manual of botany. 7th Edition, American Book
Company, New York.
Sargent, C. S.

1922. manual of the trees of north America, ed. 2. Houghton
Mifflin, New York.
Small, J. K.

1933. manual of the southeastern flora. Science Press, Lancaster, Pa.

INDEX

ACANTHACEAE.
Acanthus family...
Acer

drummondii. .

Page

136

136

122

122

negundo 122

122

122

115

115

102

102

113

72

72

72

115

113

113

113

115

115

115

115

109

rubrum

ACERACEAE

Acnida

cuspidata

Acorus

calamus

Alder. .•

Alisma

subcordatum,

ALISMACEAE

Alligator-grass

Alnus

rugosa

serrulata

Alternanthera

philoxeroides

AMARANTHACEAE.

Amaranth Family

AiMARYLLIDACEAE.

Amaryllis family 109

Ammannia

coccinea

latifolia

teres

Amorpha

f ruticosa

nitens .. .

Ampelopsis

arborea

Ampelothamnus

phyllyreifolius

Anacharls

canadensis

densa

Anchistea

virginica

Apple family

AQUIFOLIACEAE

ARACEAE

Arrow-arum

Arrow-leaf

125

125

125

125

120

120

120

122

122

132

132

75

75

75

67

67

120

121

102

103

73

Arrowroot family.

Arum family

Arundinaria

gigantea

tecta

Ash, Water

Axonopus

affinis

furcatus

Azolla

caroliniana..

Bald-rush

Bamboo-vine

Bayberry

Bayberry family

Bay ...

Red

Sweet

Bell-flower family..

Benzoin

aestivale

melissaefolium.

Berchemia

scandens

Betula

nigra

BETULACEAE....

Bidens

cernua

coronata

discoidea

frondosa

laevis

mitis

Birch family

Black-gum

Bladderwort family.

Bloodwort family

Boehmeria

cylindrica

drummondiana.

Bogbean family

Bog-hemp

Bog-mat

Bog-moss

Page

111

102

80

80

81

133

82

82

82

67

67

94
109
112
112
124
124
124
138
124
124
124
122
122
113
113
113
140
140
140
140
140
140
140
113
130
137
111
113
113
113
134
113
103
104

141

142

INDEX

Pace

Bog-moss family 104

Brasenia 117

schreberi 117

Breweria 134

aquatica 134

Bristlegrass, giant 84

Bruneria 103

Buckthorn family 122

Buckwheat family 113

Bulrush - 92

three-square 92

Burhead._ 75

Bur-reed 69

Bur-reed family 68

Buttercup 118

water 118

Buttonbush 138

Cabomba

Carolinian a

CALLITRICHACEAE.
Callitriche

heterophylla

palustris

Caltha

palustris

Camellia Family

Campanula

floridana

CAMPANULACEAE. .

117

117

121

121

121

121

118

118

124

138

138

138

Cane 80,81

giant -- 80

small 81

Canna 111

fiaccida 111

Canna family 111

Canna, golden 111

CANNACEAE 111

CAPRIFOLIACEAE 138

Carex 98

alata 101

albolutescens 101

barrattii 101

bullata 102

biixbaumii 101

cherokeensis 101

collinsii 101

comosa 102

crus-corvi - 101

decomposita 101

elliottii 102

folliculata 102

frankii. 102

Pace
Carex — Continued.

gigantea 102

glaucescens 101

grayi 102

hyalinolepis 101

intumescens 102

joorii ■ 101

laevi-vaginata 101

lanuginosa 101

lonchocarpa 102

longii 101

louisianica 102

lupulina 102

lurida 102

riparia 101

squarrosa 102

stipitata 101

stricta 100

torta 101

tribuloides 101

typhina 102

verrucosa.. 101

vulpinoidea 101

walteriana 101

Carpet-grass 82

Carrot family 130

Carya 112

aquatica 112

Castalia 117

Catchfiy-grass 81

Cattail 68

broad-leafed 68

narrow-leafed 68

Cattail family 68

CenteUa 131

erecta 131

repanda 131

Cephalanthus 138

occidentalis 138

CERATOPHYLLACEAE 116

Ceratophyllum 116

demersum." 116

echinatum 116

submersum 116

Chain-fern, Virginia 67

Chara 67

CHARACEAE 67

Cicuta 131

curtissii 131

maculata 131

Cladium.. 98

jamaicensis 98

mariscoides 98

INDEX

143

Page

Clethra 1^2

alnifolia ■ 1^2

tomentosa.

132

Dulichium

arundinaceum .

Page
87
87

CLETHRACEAE 132

Cliftonia ^21

monophylla 121

COMPOSITAE 139

Composite family 139

CONVOLVULAC^AE 134

Coontail-moss H^

Cordgrass °1

Coreopsis ^^"

nudata 140

CORNACEAE.. 130

Cow-lily 116» 117

CRASSULACEAE 119

Crataegus ^20

aestivalis 120

Crinum ^09

americamim 109

Crowfoot family H^

CRUCIFERAE 119

Cutgrass ^^> ^2

rice °^

Cvnoctonum 133

1 'i'i
mitreola ^<^^

CYPERACEAE 84

Cyperus ■ °'

erythrorhizos 88

flavescens 88

haspan 88

pseudovegetus 88

stngosus °°

virens 88

Cyrilla 121

racemiflora 121

parviflora 121

CYRILLACEAE 121

Decodon 12^

verticillatus 125

Desmothamnus 132

lucidus 132

Dianthera - - 136

Dichromena 94

colorata 94

latifolia 94

Didiplis -- 125

diandra 125

Dock, swamp H"*

Dogwood family -_ 130

Duckweed family 103

Duckweed 10'*

83
75

75

75
75

107

107

88

star.

Echinochloa-- 83

crusgalli 83

walteri —

Echinodorus

cordif olius

radicans

tenellus

Eelgrass. '5

Eichhornia -- 107

crassipes

paniculatus

Eleocharis

acicularis ^0

atropurpurea 90

baldwinii--- ^1

calva 90

cellulosa.- - ^^

elongata- - ^0

equisetoides -- ^0

flavescens 90

geniculata ^0

interstincta — °^

melanocarpa ^1

microcarpa

obtusa

olivacea

quadrangulata

robbinsii ^^

smallii. ^^

toitilis - 9^

qi

tricostata ^'^

tuberculosa ^1

. . Ql

vivipara--

Elm. water ^^^

Elm family ^^^

Erianthus ^^

brevibarbis °^

giganteus

strictus

ERICACEAE 1^2

ERIOCAULACEAE.. 106

Eriocaulon- ^^6

compressum 106

decangulare 106

lineare - --- ^06

ravenelii 106

Eryngium --- ^^^

104 aquaticum ---

91
90
90
90

84
84

130

144

INDEX

Page

Eubotrys 132

elongata 132

racemosa 132

Eupatorium 139

coelestinum 139

leucolepis 139

pubescens 139

rotundifolium 139

scabridum .- 139

semiserratum 139

verbenaefolium 139

EUPHORBIACEAE 121

Evening primrose family 126

Fan wort 117

FeatherfoiL 132

Fern family 67

Fetter-bush 132

Feverbark, Georgia 138

Figwort family 135

Fimbristylis 88

annua 88

autumnalis 88

miliacea 88

Floating-heart 134

Flowering fern family 67

Forestiera 133

acuminata 133

Fraxinus 133

caroliniana 133

pauciflora 133

profunda ^ 133

Frog-bit 76

Frog-bit family 75

Frog-fruit 134

Fuirena 93

breviseta 94

longa 93

pumila 94

scirpoidea 93

squarrosa 94

Gamagrass 84

Gentian family 133

GENTIANACEAE 133

Glabraria 124

geniculata 124

Gleditsia ._. 120

aquatica 120

tricanthos 120

Glyceria 81

septentrionalis 81

Page

Gordonia 124

lasianthus 124

GRAMINEAE 76

Grape family 122

Grass, alligator- 115

Carpet- 82

Catchfly- 81

Cord- 81

Cut- 81,82

Gama- 84

Plume- .^ 84

Switch- 83

Umbrella- 94

Water Star- 106

Wool- 93

Yellow-eyed 105

Grass family 76

Gratiola 135

ramosa 136

virginiana 135

Greenbrier, coral 109

Gyrotheca 111

tinctoria 111

Habenaria 112

repens 112

HAEMODORACEAE 111

HALORAGIDACEAE 129

Heath family 132

Hedge hyssop 135

Helanthium 75

parvulum 75

Hemp-weed 139

Herpestris 135

rotundifolia 135

Heteranthera 106

dubia 106

limosa 107

reniformis 107

Hibiscus. 122

coccineus 122

grandiflorus 123

incanus _. 123

lasiocarpus 123

militaris 123

moscheutos 123

semilobatus 123

Hickory, swamp 112

Holly family.. 121

Honeysuckle family 138

Hornwort family 116

Hottonia 132

inflata- 132

INDEX

145

Page

HYDROCHARITACEAE 75

82

82

" 130

131

Hydrochloa

caroliniensis.

Hydrocotyle

americana.

ranunculoides l^^

umbellata ^^^

verticillata.u 130

Hvdrolea ^^^

Page

no

110

"' 127

intermedia

127
repens

ISOETACEAE ^8

Iris, wild--
Iris family.
Isnardia.

affinis l^"*

corymbosa ]^^

ovata

quadrivalvis

HYDROPHYLLACEAE 134

Hydrotrirta 135

caroliniana

Hygrophila

lacust ris

Hymenocallis

crassifolia H^

kimballiae 100

laciniat a

palmeri

t ridentata

HYPERICACEAE 123

Hypericum J^^

adpressum ^■^"^

cistifolium 123

densiflorum 124

fasciculatum 124

galioides ^■'■*

myrtifolium 123

opacum

1 oo

tubulosiim ^^^

Isoetes

fiaccida

Ilea

virginica

ITEACEAE 11^

68

68

119

119

134
134

135
136
136
109

110
109
110

JUGLANDACEAE 112

JUNCACEAE -- 107

JuRCUs 107

abortivus 108

acuminatus 109

biflorus 108

brachy carpus - 108

canadensis 108

coriaceus-- 108

debilis 109

effusus 108

elliottii 109

marginatus-- 108

megacephalus 108

polycephalus- 108

repens 108

-1 no

Rcirpoides ^^°

trigonocarpus

validus

Jussiaea

virginicum.

123

Ilex-

121
121
121

cassine

coriacea

myrtifolia 121

Indigo-bush 120

IRIDACEAE 110

Iris 110

alabamensis- m

albispiritus- HI

fulva 110

hexagona

prismatica.-.

rivularis

savannarum.

Ill
111
111
111

109
108

128

angustifolia 128

decurrens- ^'^^

128

128

128

128

128

136

136

136

diffusa

grandiflora

leptocarpa

peruviana

scabra

Justicia

americana

angusta

crassifolia 13^

humilis - 13^

lanceolata 13^

ovata '

136

tripetala HO

versicolor,
virginica.

Ill
111

LABIATAE 135

1 in
Lake-cress ^'"^

LAURACEAE... 124

Laurel family 124

Ledicula 137

146

INDEX

Page

Leersia 81

hexandra 81

lenticularis 81

oryzoides 81

LEGUMINOSAE 120

Lemna 103

minima 104

minor 104

perpusilla 104

trisulca.--;. 104

valdiviana 104

LEMNACEAE 103

LENTIBULARIACEAE 137

Leucothoe 132

acuminata 132

axillaris 132

racemosa 132

Lily, alligator 109

Limnobium 76

spongia ^ 76

Lippia 134

lanceolata 134

nodiflora 134

Lizards-tail 112

Locust, swamp 120

LOGANIACEAE 133

Logania family 133

Loosestrife family 125

Lophotocarpus 75

calycinus 75

Lotus 117

Ludwigia 126

alata '. 128

alternifolia 127

arcuata 127

curtissii 127

glandulosa 127

lanceolata 128

linearis 128

linifolia 128

microcarpa 127

natans 127

palustris . 127

pilosa 127

polycarpa 127

simulata 128

spathulata 127

sphaerocarpa 127

suffruticosa 127

Ludwigianlha 127

Lycopus __ 135

americanus 135

pubens 135

Page
Lycopus — Continued.

rubellus 135

sessilifolius 135

LYTHRACEAE 125

Ly thrum 126

alatum 126

curtissii 126

fiagellare 126

ianceolatum 126

Madder family 138

Magnolia 119

virginiana 119

Magnolia family 119

MAGNOLIACEAE 119

Maidencane 83

MALACEAE 120

Mallow, rose 123

Mallow family 122

MALVACEAE 122

Manisuris 84

rugosa 84

Maple 122

ash-leaved 122

red 122

Maple family 122

MARANTACEAE 111

Mariscus 98

Marsh-marigold 118

Mayaca 104

aubletii 104

fluviatilis 104

MAYACACEAE 104

Mayhaw 120

Meadow beautj' 125

Meadow beauty family 124

MELASTOMACEAE 124

MENYANTHACEAE 134

Mermaid weed 129

Micranthemum 136

umbrosum 136

Mikania - -. 139

scandens 139

Milkwort family 120

Millet, wUd 83

Mimulus 136

alatus 136

ringens 136

Mint family 135

Mist-flower 139

Monkey-flower 136

Morning glory family 134

Mosquito Fern 67

INDEX

147

Page

Mud-plantain 107

M uskgrass family 67

Mustard family 119

Myosurus 118

minimus 118

Myrica 112

carolinensis 112

cerifera 112

MYRICACEAE 112

Myriophyllum 129

brasiliense 129

heteroph^'llum 129

laxum 129

pinnatum 129

proserpinacoides 129

Myrtle, wax _. 112

NAJADACEAE 69

Najas 71

flexilis 71

gracilis 71

guadalupensis 71

marina 71

Nasturtium 119

officinale 119

Negundo 122

Nelumbo 117

lutea 117

nucifera 118

Nemastylis 110

floridana 110

Neobeckia 119

aquatica 119

Nettle family 113

Never-wet 102

Nitella 67

Nuphar 116

advena 117

bombycinum 116

chartaceum 117

fluviatile 117

orbiculatum 116

sagittaefolium 116

ulvaceum 116

Nymphaea 117

elegans 117

flava 117

odorata 117

Nymphaea 116

advena 117

bombycina 116

chartacea ■ 117

fiuvialilis 117

Fag«

Nymphaea — Continued.

macrophylla 117

orbiculata 116

sagittaefolia 116

ulvacea 116

NYMPHAEACEAE 116

Nymphoides 134

aquaticum 134

cordatum 134

lacunosum 134

Nyssa 130

aquatica 130

biflora 130

ogeche 130

ursina 130

Ogeche lime 130

OLEACEAE 133

Olive family 133

ONAGRACEAE 126

ORCHIDACEAE 112

Orchid family 112

Orontium 102

aquaticum 102

Orpine family 119

Osmunda ■ 67

regalis 67

OSMUNDACEAE 67

Oxypolis 131

filiformis 131

Paint-root 111

Panicum 82

agrostoides 83

condensum 83

gymnocarpon 83

hemitomum 83

tenerum 83

virgatum 83

Parrot's-feather 129

Paspalum 82

dissectum 82

distichum 82

praecox 82

repens 82

Pea family 120

Peltandra 103

glauca 103

virginica 103

Pennywort, water 130

Perithorum. - .-. 119

sedoides 119

Pepper family 112

148

INDEX

Page

Pepper-vine 122

Persea 124

pubescens 124

Persicaria 114

Phyla 135

Pickerel-weed 107

Pickerel-weed family 106

Pilostaxis .-. 120

Pimpernel, water 132

PINACEAE 68

Pinckneya 138

pubens 138

Pine family 68

Pine, pond 68

Pinus 68

serotina 68

PIPERACEAE 112

Pipewort 106

Pipewort family 106

Pistia 103

stratiotes 103

Planera 113

aquatica 113

Pluchea 139

foetida 139

imbricata 139

petiolata 139

quitoc 139

Plumegrass 84

brown 84

giant- 84

narrow _- 84

Polygala 120

baldwinii 120

cymosa 120

lutea 120

ramosa 120

rugelii 120

POLYGALACEAE 120

POLYGONACEAE 113

Polygonum 114

coccineum 114

densiflorum 115

hirsutum 115

hydropiper 115

hydropiperoides 115

lapathifolium 115

longistylum 115

opelousanum 115

pensylvanicum 115

persicaria 115

punctatum 115

sagittatum 114

setaceum 115

Page

POLYPODIACEAE 67

Pondweed 69

horned 71

Pondweed family 69

Pontederia 107

cordata 107

lanceolata 107

PONTEDERIACEAE 106

Potamogeton 69

americanus 70

amplifolius 70

angustifolius 71

berchtoldi 71

bicupulatus 70

bupleuroides 71

capillaceus 70

diversifolius 70

epihydrus 70

foliosus 71

gramineus ^ 71

illinoensis 71

natans 70

nodosus 70

pectinatus 71

perfoliatus 71

pulcher 70

pusillns 71

Primrose family 132

PRIMULACEAE 132

Privet, swamp 133

Proserpinaca 129

amblygona 129

intermedia 129

palustris 129

pectinata 129

plalycarpq 129

Psilocarya 94

corymbifera 94

nitens 94

scirpoides 94

Ptilimnium 131

capillaceum 131

costatum 131

nodosum 131

nuttallii- 131

Purslane, water 125

Quillwort-. -. 68

Quillwort family 68

Ranunculacere 118

Ranunculus 118

ambigens 118

delphinifolius 118

INDEX

149

Pace
Ranunculus — Continued.

flabellaris 118

laxicauiis 118

lindheimeri 118

obiusiusculus 118

pusillus 118

sceleratus 118

Rattan-vine 122

RHAMNACEAE 122

Rhexia 124

aristosa 125

cubensis 125

lanceolata 125

mariana 125

nashii 125

parviflora 125

stricta 125

virginica 125

Rhynchospora 94

caduca 97

capitellata 96

careyana 96

cephalantha 96

chalarocephala 96

chapmanii 96

compressa 97

corniculata 96

cymosa 97

decurrens 97

edisoniana 97

fascicularis 97

filifolia.... 97

fusca 97

globularis 97

glomerata 96

gracilenta 97

harperi 97

harveyi 97

intermixta 96

inundata 96

leptocarpa 96

macrostachya 96

microcarpa 97

microcephala 96

miliacea 97

mixta 97

patula 97

perplexa 97

schoenoides 97

stipitata 97

torreyana 97

tracyi 96

wrightiana 97

Page

Riccia 67

fluitans _ 67

RICCIACEAE 67

Ricciocarpus 67

natans 67

Rice, wild 81

Rorippa 119

sessiliflora 119

Rosa 119

palustris 119

ROSACEAE 119

Rose family 119

Rose, swamp 119

Rotala _ 125

ramosior 125

Royal-fern _ 67

RUBICEAE 138

Rvfacer 122

Rumex 113

fasciculatus 114

verticillatus 114

Ruppia 71

maritima 71

Rush, bald 94

Soft- 108

White-top 94

Rush family. 107

Sabatia 133

calycina 133

campanulata 133

decandra 133

foliosa 133

harperi 133

Sacciolepis 83

striata 83

Sagittaria 72

angustifolia 74

chapmanii 74

cycloptera 74

falcata 74

filiformis 74

graminea 74

isoetiformis 74

lancifolia 74

latifolia 74

longirostra 74

macrocarpa 75

mohrii 74

montevidensis 74

platyphylla 73

rigida 74

subulata 74

150

INDEX

Page

74

75

123

123

112

112

113

113

112

113

113

67

67

138

138

simpsonii 138

Samolus 132

pauciflorus 132

Saururus 112

112

Sagittarla — Continued.

teres

viscosa

St. John's-wort

St. John's-wort family.

SALICACEAE

Salix

amphibia

harbisonii

interior

longipes

nigra

SALVINIACEAE

Salvinia family

Sambucus

canadensis

cernuus

Scirpus

americanus

atrovirens

calif ornicus

cubensis

cyperinus

debilis

divaricatus

eriophorum

etuberculatus.

fontinalis

georgianus

lineatus

olneyi

polyphyllus-..
subterminalis.

sylvaticus

validus

Scleria

baldwinii

georgiana

gracilis

hirtella

paucifiora

muhlenbergii.
verticillata

91

92

93

92

93

93

92

93

93

92

93

93

. 93

92

93

92

93

.._ 92

98

98

98

98

98

98

98

98

Sclerolepis 139

uniflora 139

SCROPHULARIACEAE 135

Scutellaria 135

laterifolia 135

Sedge family 84

Setaria

magna

Sium

cicutaefolium.

suave

Skullcap

Smartweed

SMILACACEAE.

Page

84

84

131

131

131

135

115

109

Smilax family 109

Smilax 109

laurifolia 109

waiter! 109

Snakeroot 130

Soft-rush 108

SPARGANIACEAE 68

Sparganium 68

americanum 69

eurycarpum 69

Spartina 81

bakeri 81

spartinae 81

Spice-bush 124

Spikerush 89

knotted 90

square-stemmed 90

Spirodela 104

polyrhiza 104

Spurge family 121

Star-grass, water 106

Starwort, water 121

Stillingia 121

aquatica 121

Stomoisia 137

cornuta 137

juncea 137

Stonecrop, ditch 119

Swamp-dock 114

Swamp-potato 74

Swamp privet 133

Sweet-flag 102

Switchgrass 83

124

68

.... 68

68

111

111

geniculata HI

Thallose liverwort family 67

THEACEAE 124

TitL.. 121

Tamala

Taxodium

distichum

imbricarium.

Thalia

dealbata

INDEX

151

Page

Titi family 121

Trapa 66

natans 66

Triadenum 123

Tripsacum 84

dactyloides 84

Tupelo-gum 130

Typha 68

angustifolia 68

latifolia 68

TYPHACEAE 68

ULMACEAE 113

UMBELLIFERAE 130

Umbrella-grass 94

URTICACEAE 113

Utricularia 137

biflora 138

cprnuta 137

fibrosa 138

floridana 138

foliosa 138

gibba 138

inflata 137

macrorhiza 138

pumila 138

purpurea 137

radiata 137

resupinata 137

virgatula 137

vulgaris 138

VaUisneria 75

americana 75

VERBENACEAE 134

Verbena family 134

Vesiculina 137

Virginia willow family 119

VITACEAE 122

Walnut family 112

Water-chestnut 66

Water-chinquapin 117

Water-cress 119

Waterleaf family 134

Water-lettuce 103

Water-lily 117

blue 117

white 117

yellow 117

Page

Water-lily family 116

Watermeal 103

Water milfoil family 129

Water-pepper 115

Water plantain family 72

Water-shield 117

Water starwort family 121

Waterweed 75

White alder family 132

Widgeon-grass 71

Wild rice 81

Willow 112, 113

black 113

sandbar 112

Virginia 119

water 125

Willow family 112

Wolffia 103

Columbiana 103

punctata 103

Wolffiella 103

floridana 103

Wool-grass 93

XYRIDACEAE 104

Xyris 104

ambigua 105

baldwiniana 105

caroliniana 105

communis 105

difformis 106

elata 105

elliottii 106

fimbriata 106

iridifolia 105

jupacai 105

serotina 106

smalliana 106

stricta 105

torta 105

Yaupon 121

Yellow-eyed grass 105

Yellow-eyed grass family 104

Zannichellia 71

palustris 71

Zizania 81

aquatica 81

Zizaniopsis 82

miliacea 82

t U. S. GOVERNMENT PRINTING OFFICE : 1963 O - 673260