•21

kTION BULLETIN 527

M arch v 1984

U Owl

luatic Vascular Plants of New England:
Part 7. Cabombaceae, Nymphaeaceae,
Nelumbonaceae, and Ceratophyllaceae

by
C. B. Hellquist and G. E. Crow

NEW HAMPSHIRE

AGRICULTURAL EXPERIMENT STATION

UNIVERSITY OF NEW HAMPSHIRE

DURHAM, NEW HAMPSHIRE 03824

University of New Hampshire Library'

ISSN: 0077-8338

kTION BULLETIN 527

March, 1984

IU

juatic Vascular Plants of New England:
Part 7. Cabombaceae, Nymphaeaceae,
Nelumbonaceae, and Ceratophyllaceae

by
C. B. Hellquist and G. E. Crow

NEW HAMPSHIRE

AGRICULTURAL EXPERIMENT STATION

UNIVERSITY OF NEW HAMPSHIRE

DURHAM, NEW HAMPSHIRE 03824

5

ACKNOWLEDGEMENTS

We wish to thank Edward G. Voss, Carroll E. Wood, and Donald
H. Les for their helpful comments on the manuscript. We are also
grateful to the curators of the following herbaria for use of their
collections: BRU, CONN, CUW, GH, HNH, KIRI, MASS, MAINE,
NASC, NCBS, NHA, NEBC, VT, YU. A special thanks is extended to
Pamela Bruns Brayton who prepared the illustrations. Permission to
redraw some figures from Fassett's Manual of Aquatic Plants used in
Figure 7 was kindly provided by the University of Wisconsin Press.

This work is a result of research sponsored by the New Hampshire
Agricultural Experiment Station. The NHAES reserves the right to
reproduce, publish or otherwise use, and to authorize others to use, the
work for Government purposes notwithstanding notice of copyright.

Copyright £ 1984 by the University of New Hampshire. No part of this work may be
reproduced in any manner without permission from the authors and the University of
New Hampshire.

Programs of the New Hampshire Agricultural Experiment Station are open to all
persons without regard to race, color, national origin or sex. The University of New
Hampshire is an Affirmative Action/Equal Opportunity Employer.

UNH LIBRARY

3 MbOD DOblfl M75S

ABSTRACT

This paper is the seventh in a series of reports on the aquatic and
wetland flora of New England. It treats all species of the Cabombaceae,
Nymphaeaceae, Nelumbonaceae, and Ceratophyllaceae occurring in
New England and includes keys, comments on taxonomy and nomen-
clature, habitat and distributional information, water chemistry data,
illustrations, and dot maps. Those species regarded as rare and
endangered in the New England Region or in one or more of the six
New England States are also noted. One species, Nymphaea tetragona,
is presently under consideration by the U.S. Fish and Wildlife Service
for listing under the Endangered Species Act of 1973.

KEY WORDS: Aquatic Plants, New England Flora, Taxonomy, Cabombaceae,
Nymphaeaceae, Nelumbonaceae, Ceratophyllaceae, Cabomba, Brasenia, Nymphaea.
Nuphar, Nelumbo. Ceratophyllum. Fanwort. Water-shield, Water-lily, Pond-lily, Yellow
Water-lily. Spatterdock, Cow-lily, Lotus. Water Chinquapin, Coontail, Hornwort.

TABLE OF CONTENTS

Page

INTRODUCTION 1

CABOMBACEAE 2

Cabomba 2

Cabomba earoliniana 2

Brasenia 2

Brasenia schreberi 6

NYMPHAEACEAE 6

Nymphaea 6

Key to Species 6

Nymphaea odorata 9

Nymphaea tuberosa 9

Nymphaea tetragona 9

Nuphar 10

Key to Species 10

Nuphar pumila 13

Nuphar X rubrodisca 13

Nuphar uariegata 13

Nuphar advena 19

NELUMBONACEAE 19

Nelumbo 19

Nelumbo lutea 19

CERATOPHYLLACEAE 19

Ceratophyllum 19

Key to Species 21

Ceratophyllum demersum 21

Ceratophyllum echinatum 21

Literature Cited and Selected References '. . . . 24

n

Aquatic Vascular Plants of New England:
Part 7. Cabombaceae, Nymphaeaceae,
Nelumbonaceae, and Ceratophyllaceae

by
C. B. Hellquist and G. E. Crow1

INTRODUCTION

This is the seventh in a series of reports on the aquatic and
wetland flora of New England. These reports are intended to aid
conservationists, fish and game personnel, consultants, botanists,
and students in the identification of aquatic plants. The coverage is
strictly New England but is of value throughout the northeast. Data
have been gathered from herbaria in New England and from personal
field work.

The chemical data included represent samples from many waters
throughout New England. The alkalinity readings are total alkalin-
ity, expressed as milligrams per liter (mg/1) CaC03. The number of
observations is given in parentheses following alkalinity and pH
values. Since pH and alkalinity vary greatly during the day, the
values are only indicative of the water quality.

The rare and endangered plant lists referred to are those prepared
for each of the six New England states by the New England Botanical
Club in cooperation with the United States Fish and Wildlife Service,
Office of Endangered Species, Newton Corner, MA (RI — Church and
Champlin, 1978; MA — Coddington and Field, 1978; VT — Country-
man, 1978; ME — Eastman, 1978; CT — Mehrhoff, 1978; NH — Storks
and Crow, 1978). Taxa indicated as rare, threatened or endangered for
the entire New England Region are also noted (Crow et ai, 1981,
Rhodora 83: 259-299).

We invite comments and/or criticisms on this treatment. Infor-
mation on any species omitted or any additional localities will be
welcomed. If anyone is interested in specific localities of any of the
species indicated on the dot maps, please contact us.

'Dr. C. Barre Hellquist, Department of Biology, North Adams State College.
North Adams, MA 01247.

Dr. Garrett E. Crow, Department of Botany and Plant Pathology, Nesmith Hall,
University of New Hampshire, Durham, NH 03824.

CABOMBACEAE

1. Submersed leaves opposite, dissected into linear segments (fig. 1);
floating leaves small, inconspicuous, oblong to linear-elliptic, pel-
tate, less than 2 cm long, subtending flowers (fig. 1); submersed
portions of plants lacking mucilaginous coating; flowers white to
pinkish; stamens 3-6.
1. Cabomha

1. Submersed leaves absent, except on young plants, then alternate
(fig. 2B); floating leaves prominent, peltate, elliptical, 2-10 cm long
(fig. 2); submersed portions of plants typically with a mucilaginous
coating; flowers red-purple; stamens 12 or more.

2. Brasenia

Cabomba (Fanwort)

Perennial, arising from short rhizomes with fibrous roots;
submersed leaves opposite, petioled, fan-like, with finely dissected
divisions; floating leaves alternate, small, oblong to linear-elliptic,
peltate; flowers usually solitary, borne in axils of floating leaves;
perianth white to pinkish, about 12 mm long; carpels (2-)3(-4), separ-
ate; fruit leathery, indehiscent, 3-seeded follicle.

1. Cabomba caroliniana Gray Fig. 1, Map 1

Locally abundant and weedy in acidic waters of southern New
England. This aggressive weed was first reported in New England
from Cranston, Rhode Island in 1933. Herbicides and mechanical
harvesting have proven completely ineffective for controlling this
species. Range extends from southern New Hampshire and Massa-
chusetts west to New York, Pennsylvania, southern Michigan, south-
ern Illinois, and Missouri, south to Florida, eastern Oklahoma, and
eastern Texas.

alkalinity: mean 15.8; range 3.5-35.0 mg/1; (13)

pH: mean 6.5; range 5.9-6.8; (10)

Brasenia (Water Shield)

Perennial, arising from creeping rhizomes; all leaves floating
(submersed leaves present only on young plants), elliptic, peltate;
submersed parts typically covered with a thick, mucilaginous coat-
ing; flowers solitary, axillary; perianth red-purple, 12-20 mm long;
carpels 4-10, separate; fruit a leathery, indehiscent, 1-2 seeded follicle.

floating leaf

Figure 1.
Cabomba caroliniana: habit * ¥2.

Figure 2.
Brasenia schreberi: A. habit * '/•>. B. submersed leaves
of young plant * V->. C winter bud with thick mucilagi-
nous coating « V>. D. flower "I.E. section of flower
showing separate carpels * 1 '/•>.

1. Brasenia schreberi Gmel. Fig. 2, Map 2

Common in slow moving and standing waters throughout New
England. Range extends from Prince Edward Island west to southern
Quebec, southern Ontario, and Minnesota, south to Florida and
Texas; southern British Columbia to Oregon; Mexico and Central
America.

alkalinity: mean 15.9 mg/1; range 2.5-111.5 mg/1; (53)

pH: mean 6.6; range 5.7-9.5; (51)

NYMPHAEACEAE

1. Flowers white to pinkish, broadly open (figs. 3,4); sepals 4, greenish;
petals numerous, conspicuous, elliptic to spatulate to oblanceolate;
stigmas radiate from globose ovary summit extending into linear,
incurved sterile appendages; leaves orbicular, lobes with recurved
tips (fig. 3A,D), venation essentially palmate (fig. 3A,D).
1. Nymphaea

1. Flowers yellow, sometimes greenish or reddish, subglobose (fig. 7);
sepals 5-6(-9); petals numerous, strap-like, usually shorter than,
but resembling the stamens, recurved; stigmas sessile, radiate on a
disc (fig. 7), appendages lacking; leaves orbicular-reniform, ovate
to oblong, lobes rounded at tip (figs. 5,6), venation essentially pin-
nate (fig. 5B,D).
2. Nuphar

Nymphaea (Water-lily, Pond-lily)

Perennial, arising from rhizomes; leaves submersed, floating
and/or emergent, deeply cleft, long-petioled; flowers showy; sepals 4,
greenish; petals numerous, white to pink, the inner ones usually tran-
sitional to stamens; fruit a leathery berry; seeds arillate, maturing
underwater.

Key to Species

1. Leaves orbicular to ovate in outline, 7-30 cm wide, sinus typically
narrow or closed (fig. 3A,D); flowers 7-30 cm broad, petals 17-32.
2. Petioles green, not striped; lower surface of leaf red to purple
(rarely green); petals elliptic, subacute at tip (fig. 3B,C).

1 . N. odorata

2. Petioles green with brown-purple stripes; lower surface of leaf
green (rarely faint red-purple); petals spatulate to oblanceolate,
rounded at tip (fig. 3E.F).
2. N. tuberosa

Figure 3.
Nymphaea odorata: A. leaf * M>. B. flower * lh. C. series
showing transition from petals to stamens * lA.
Nymphaea tuberosa: D. leaf * lh. E. flower * lh. F. series
showing transition from petals to stamens * V*.

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1 . Leaves ovate to obovate in outline, 4-9 cm wide, sinus typically open
with widely divergent lobes (fig. 4); flowers 3.3-8 cm broad, petals
8-17.
3. N. tetragona

1. Nymphaea odorata Ait. Fig. 3, Map 3

Extremely common throughout New England in sluggish
streams, ponds, and lakes. Light pink-flowered individuals are fre-
quently encountered and are treated by some authors as forma rubra
Guillon. Occasionally plants with dark pink to light red flowers are
found which are likely to be the European Nymphaea alba L. forma
rosea Hartm., differentiated from N. odorata by having 20-24 petals
which are rounded at the tips. Nymphaea odorata has 17-32 petals
which gradually taper to subacute tips. Range extends from New-
foundland and southwestern Quebec west to Ontario, Minnesota, and
Manitoba, south to Florida, Iowa, Nebraska, Kansas, Oklahoma,
Texas, and Arizona.

alkalinity: mean 25.0 mg/1; range 2.0-141.5 mg/1; (121)

pH: mean 7.0; range 5.3-9.5; (117)

2. Nymphaea tuberosa Paine Fig. 3, Map 4

Common in alkaline waters of the Lake Champlain Valley of
Vermont, uncommon elsewhere in New England, but sometimes
planted as an ornamental. Floating leaves are often very large (up to
40 cm wide) and plants along the shoreline may have leaves elevated
above the surface. Two characters often utilized to distinguish
N. odorata and N. tuberosa are time of day flowers are open and the
degree of flower odor. Neither of these traits are reliable. Population
and transplant studies by Williams (1970) suggested that characters
distinguishing N. tuberosa from N. odorata may not be constant. In
calcareous waters of the Lake Champlain Valley the two taxa are
easily distinguished. Likewise, introduced plants of N. tuberosa in
acidic waters of eastern New England retain their distinctive features.
Hence, we presently continue to recognize them as two species. Range
extends from southwestern Quebec west to northern Ontario, Minne-
sota, and Nebraska, south to Maryland,^ Ohio, Indiana, Illinois,
Arkansas, and northeastern Oklahoma.
Rare and endangered plant lists: Massachusetts, Connecticut

alkalinity: mean 59.0 mg/1; range 10.0-153.0 mg/1; (21)

pH: mean 7.6; range 6.8-8.6 (21)

3. Nymphaea tetragona Georgi Fig. 4, Map 5

Rare, in quiet streams and protected waters of moderate alkalin-
ity of northern and northwestern Maine. The North American taxon

10

is subsp. leibergii (Morong) Porsild. Range extends from Quebec and
northern Maine west to Isle Royale, Michigan, Saskatchewan,
Northwest Territories, Alaska, and British Columbia, south to
northwestern Montana, northern Idaho, and Washington.
Rare and endangered plant lists: Maine, New England; under consid-
eration by the U.S. Fish and Wildlife Service, Office of Endangered
Species for listing under the Endangered Species Act of 1973.

alkalinity: mean 24.8 mg/1; range 13.5-40.0 mg/1; (4)

pH: mean 7.1; range 7.0-7.3; (4)

Nuphar (Yellow Water-lily, Spatterdock, Cow-lily)

Perennial, arising from large, cylindrical, creeping rhizomes;
leaves submersed when young, becoming floating and/or erect,
blades deeply cleft, with long petioles; flowers globose, floating or
elevated above surface; sepals 5-6(-9), yellow, sometimes greenish or
reddish tinged; petals numerous, yellow, small, strap-like resembling
the stamens; stamens numerous, filaments flat; stigmas sessile,
radiate on a disc; fruit an ovoid, leathery berry, with numerous non-
arillate seeds per locule, maturing above the water surface.

The treatment of Nuphar by E. O. Beal (1956), not followed here,
recognized only one species, N. lutea (L.) Sibth. and Smith, in the
world, with nine subspecies.

Key to Species

1. Leaf blades of mature plants 3.5-20 cm long, 3.5-14.5 cm wide; fruit

conspicuously constricted below the stigmatic disc (fig. 7B,D).

2. Flowers 2 cm or less wide; stigmatic disc with 6-10 deep crena-

tions (fig. 7B), leaf blades 3.5-10 cm long, 3.5-7.5 cm wide; blade

notch two-thirds or more the length of the midrib (fig. 5A).

1 . N. pumila

2. Flowers 3 cm or more wide; stigmatic disc with 8-15 shallow
crenations (fig. 7D); leaf blades 5-20 cm long, 4.5-14.5 cm wide;
blade notch one-half the length of the midrib (fig. 5B).

2. N. Xrubrodisca

1. Leaf blades of mature plants 7.0-40 cm long, 4.0-25 cm wide; fruit
only slightly constricted, or not constricted below the stigmatic
disc (fig. 7F,H).

3. Petiole strongly flattened above and winged (fig. 6B); leaves
usually floating (fig. 6A); fruit and inner surface of sepals often
maroon or red.

3. N. uariegata

11

Figure 4.
Nymphaea tetragona: habit showing both floating
leaves and submersed leaves * Vfe.

12

5

si

13

3. Petiole terete, not winged (fig. 5D); leaves mostly erect, elevated
above the water surface (fig. 5C); inner surface of sepals and fruit
green and/or yellow.
4. N. advena

1. Nuphar pumila (Timm) DC. Figs. 5, 7, Map 6

Widely scattered in quiet waters of northern portions of Maine,
New Hampshire, and Vermont; rare elsewhere in New England. This
species once occurred more frequently throughout the region, but
recent attempts to relocate it in southern New England have been
unsuccessful. This taxon has long been treated as N. microphyllum
(Pers.) Fern. More recently Beal (1956) has treated this as N lutea
subsp. pumila (Timm) Beal which also occurs in northern Europe.
Range extends from Newfoundland west to Manitoba, south to Nova
Scotia, northern Michigan, northern Wisconsin, and northeastern
Minnesota.
Rare and endangered plant list: Maine

alkalinity: mean 36.1 mg/1; range 3.5-103.5 mg/1; (9)

pH: mean 7.4; range 6.5-9.5; (8)

2. Nuphar Xrubrodisca Morong Figs. 5, 7, Map 7

Widely scattered in quiet waters throughout New England, but
especially common in the Lake Champlain Valley of Vermont. This
taxon is believed to be a fertile hybrid between N pumila and
N. variegata. The stigmatic disc of the flower and fruit is usually
bright red. Young plants of N. variegata may be mistaken for N.
Xrubrodisca. Range extends from Newfoundland west to eastern On-
tario, south to Nova Scotia, Connecticut, New Jersey, eastern
Pennsylvania, New York, northern Michigan, northern Wisconsin,
and eastern Minnesota.
Rare and endangered plant list: Vermont

alkalinity: mean 31.3 mg/1; range 3.5-57.5 mg/1; (8)
pH: mean 7.4; 6.7-8.2; (8)

3. Nuphar variegata Durand Figs. 6, 7, Map 8

Extremely common in slow moving waters throughout New En-
gland. This is one of the most common aquatic species in the region.
Beal (1956) treated this taxon as N lutea subsp. variegata (Durand)
Beal. Range extends from Newfoundland and Labrador west to
Yukon, south to Delaware, northeastern Pennsylvania, northern
Ohio, northern Indiana, northern Illinois, South Dakota, Nebraska,
and Montana.

alkalinity: mean 27.7 mg/1; range 2.0-132.5 mg/1; (186)

pH: mean 7.0; range 5.0-9.8; (181)

14

Figure 5.
Nuphar pumila: A. leaves * Vfe.
Nuphar Xrubrodisca: B. leaf * xk.

Nuphar advena: C. habit showing characteristically
emergent leaf blades. D. leaf * lh.

15

Figure 6.
Nuphar variegata: A. habit showing characteristically
floating leaves. B. leaf * Vfe.

16

Figure 7.
Nuphar pumila: A. flowers x '/fe. B. fruits * '/.>. Both
redrawn from Fassett.

Nuphar ■ rubrodiaca:C flower ■ 1. 1), fruit ■ 1, redrawn
from Fassett.

Nuphar variegata: F. flower - 1. F. fruit * 1. Both
redrawn from Fassett.
Xuphar advena: (i. flower * '/j. H. flower * V>.

17

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18

19

4. Nuphar advena (Ait.) Ait. f. Figs. 5, 7, Map 9

Locally abundant in the intertidal zone of Merrymeeting Bay,
Sagadahoc Co., Maine and at a few locations along the coast of
Connecticut. Beal (1956) recognized this taxon as N. lutea subsp.
macrophylla (Small) Beal. Range extends from southern coastal
Maine and coastal Connecticut west to central New York, Pennsylva-
nia, Ohio, southern Michigan, southern Wisconsin, and southeastern
Nebraska, south to Florida, Texas, and eastern Mexico.

NELUMBONACEAE

Nelumbo (Lotus, Water Chinquapin)

Perennial, arising from rhizomes; leaves large, circular, peltate,
elevated high above the water (fig. 8) or floating; flowers large,
showy; perianth sulfur-yellow, 12-25 cm broad, elevated above the
water; stamens numerous, readily deciduous; carpels numerous,
separate, imbedded in a broad, flat-topped receptacle; fruits indehis-
cent nutlets, often remaining in cavities of the woody receptacle.

1. Nelumbo lutea (Willd.) Pers. Fig. 8, Map 10

Widely scattered throughout southern New England in shallow
ponds and along shores. The localities in New England are probably
the result of introductions or escapes from cultivation. A large popula-
tion occurs at the Great Meadows National Wildlife Refuge, Concord,
Massachusetts. Ward (1977) notes that because the name Nelumbo
pentapetala (Walt.) Fern, is of uncertain application, nomenclatural
stability is better served by the use of Nelumbo lutea (Willd.) Pers. for
the American Lotus. Range extends from southeastern Maine and
Massachusetts west to New York, southern Ontario, Minnesota, and
Iowa, south to Florida, Oklahoma, and eastern Texas.

CERATOPHYLLACEAE

Ceratophyllum (Coontail, Hornwort)

Perennial, free-floating submersed aquatic, lacking roots; leaves
whorled, sessile or with short petioles, dichotomously divided into
narrow segments (seedling leaves often opposite, simple); plants
monoecious; flowers unisexual, axillary, one to several per node; fruit
a 1-seeded, ovoid-oblong achene.

20

nutlet

Figure 8.
Nelumbo lutea: A. habit. B. leaf * '/«. C flower * XM. D.
woody receptacle with fruits * 'A.

21
Key to Species

1. Principal leaves forked no more than two orders (no pair of ultimate
segments results from more than two consecutive forkings of the
leaf axis) (fig. 9B); leaf segments with distinct serrations (fig. 9B),
the marginal teeth with wide bases (fig. 9C); fruit smooth or slightly
warty, with two basal spines, marginal spines lacking (fig. 9D); first
seedling leaves simple.
l.C. demersum

1. Principal leaves often forked 3-4 orders (ultimate segment pairs
result from up to 3-4 consecutive forkings of the leaf axis) (fig. 9E,F);
leaf segments lacking distinct serrations, marginal teeth, when
present, with narrow base (fig. 9F); first seedling leaves at least
once divided.
2. C. echinatum

1. Ceratophyllum demersum L. Fig. 9, Map 11

Common in shallow quiet waters throughout New England. Fruit
on this and C. echinatum are uncommon, hence the vegetative charac-
ters are frequently used for identification. Range extends from Quebec
and Maine west to northern British Columbia, south throughout the
United States to Mexico.

alkalinity: mean 51.6 mg/1; range 5.5-151.0 mg/1; (64)

pH: mean 7.3; range 5.9-8.9; (62) ^

2. Ceratophyllum echinatum A. Gray Fig. 9, Map 12

Locally abundant in quiet waters of southern New England.
Although Lowden (1978) regards this taxon as conspecific with the
Old World C. muricatum Cham., recent studies by Donald Les (pers.
comm.) have supported the recognition of the two taxa as distinct
species. Range extends from southwestern New Brunswick and cen-
tral Maine west to New York, Ohio, Michigan, Illinois, and Minnesota,
south to Florida, Iowa, Missouri, Arkansas, and Texas.
Rare and endangered plant list: Vermont

alkalinity: mean 25.1 mg/1; range 6.0-120.0 mg/1; (7)

pH: mean 6.8; range 5.7-7.8; (6)

22

Figure 9.
Ceratophyllum demersum: A. habit * '/->. B. leaves * 1 *&.
C. leaf segment showing broad-based marginal tooth
*4Vfe. D. fruit »3.

Ceratophyllum echinatum: E. leaf * lVfe. F. spinulose
leaf segment * 4'/^. G. fruit * 3.

23

24

Literature Cited and
Selected References

Aboy, H. E. 1936. A study of the anatomy and morphology oiCerato-
phyllum demersum. M. S. Thesis, Cornell Univ., Ithaca, N.Y.

Adams, F. S. 1969. Winter bud production and function in Brasenia
schreberi. Rhodora 71: 417-433.

Baillon, H. 1871. Monographic des Nymphaeacees. Hist. PI. 3: 77-104.

Bates-Smith, F. C. 1968. Chemotaxonomy of Nuphar luteum (L.) Sm.
Phytochemistry 7: 459.

Beal, E. 0. 1955. Taxonomic revision of the genus Nuphar Sm. Ph. D.
dissertation, Iowa State University, Ames, Iowa.

Beal, E. O. 1956. Taxonomic revision of the genus Nuphar Sm. of
North America and Europe. J. Elisha Mitchell Sci. Soc. 72:
317-346.

Beal, E. O. and R. M. Southall. 1977. Taxonomic significance of exper-
imental selection by vernalization in Nuphar (Nymphaeaceae).
Syst. Bot. 2: 49-60.

Beal, W. J. 1900. Notes on Cabomba caroliniana A. Gray. Bull. Torrey
Bot. Club 27: 86.

Chrysler, M. A. 1938. The winter buds of Brasenia. Bull. Torrey Bot.
Club 65: 277-283.

Conard, H. S. 1904. Phyllody in Nelumbo. Trans. Proc. Bot. Soc. Penn.
1: 350-351.

Conard, H. S. 1905. The water-lilies, a monograph of the genus Nym-
phaea. Publ. Carnegie Inst. Wash. No. 4.

Conard, H. S. 1916. Nymphaea and Nuphar again. Rhodora 18:
161-163.

Conard, H. S. 1936. Water-lilies, monocots or dicots? Amer. Bot. 42:
104-107

Cutter, E. G. 1961. The inception and distribution of flowers in the
Nymphaeaceae. Proc. Linn. Soc. London 172: 93-100.

DePoe. C. E. 1961. Relationships within the genus Nuphar Sm. (Nym-
phaeaceae) in the Carolinas. M. S. Thesis, North Carolina State
University, Raleigh, NC.

DePoe, C. E. and E. O. Beal. 1969. Origin and maintenance of clinal
variations in Nuphar (Nymphaeaceae). Brittonia 21: 15-28.

Dormer, K. J. and E. G. Cutter. 1959. On the arrangement of flowers on
the rhizome of some Nymphaeaceae. New Phytol. 58: 176-181.

25

Farwell, O. A. 1936. The color of the flowers of Nelumbo pentapetala.
Rhodora 38: 272.

Fassett, N. C. 1953. A monograph of Cabomba. Castanea 18: 116-128.

Fassett, N. C. 1953a. North American Ceratophyllum. Comun. Inst.
Trop. Invest. Cient. 2: 25-45.

Fernald, M. L. 1919. Nymphozanthus, the correct name for the cow
lilies. Rhodora 21: 183-188.

Fernald, M. L. 1934. The name of the American lotus. Rhodora 36:
23-24.

Gleason, H. A. 1947. The preservation of well-known binomials. Phy-
tologia 2: 201-212.

Gray, A. 1837. Remarks on the structure and affinities of the order
Ceratophyllaceae. Ann. Lyceum Nat. Hist. New York 4: 41-50.

Haines, R. W. and K. A. Lye. 1975. Seedlings of Nymphaeaceae. J.
Linn. Soc, Bot. 70: 255-265.

Hall, T. F. and W. T. Penfound. 1944. The biology of the American
Lotus, Nelumbo lutea (Willd.) Pers. Amer. Midi. Nat. 31: 744-758.

Heslop-Harrison, Y. 1955. Nuphar Sm. J. Ecol. 43: 342-364.

Jones, E. N. 1931. The morphology and biology of Ceratophyllum
demersum. Univ. Iowa Stud. Bot. 13: 11-46.

Kosakai, H., M. F. Moseley, and V. I. Cheadle. 1970. Morphological
studies of the Nymphaeaceae V. Does Nelumbo have vessels?
Amer. J. Bot. 57: 487-494.

Lawson, G. 1889. On the Nymphaeaceae Trans. Roy. Soc. Canad.
6: 97-125.

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26

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27

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ERRATUM — Aquatic Plants of New England:
Part 6. Trapaceae, Haloragaceae, Hippuridaceae

Page 2, lines 2-3 should read:

"adventitious roots opposite, finely dissected"

Station Bulletins of Botanical Interest

Grasses of New Hampshire. I. Tribes Poeae (Festuceae) and Triticeae
(Hordeae). A. R. Hodgdon, G. E. Crow, and F. L. Steele. Bull. No.
512. 1979.

The Flora of Plum Island, Essex County, Massachusetts. M. J.
McDonnell. Bull. No. 513. 1979.

Aquatic Vascular Plants of New England: Part 1. Zosteraceae, Pota-
mogetonaceae, Zannichelliaceae, Najadaceae. C. B. Hellquist and
G. E. Crow. Bull. No. 515. 1980.

Aquatic Vascular Plants of New England: Part 2. Typhaceae and
Sparganiaceae. G. E. Crow and C. B. Hellquist. Bull. No. 517. 1981.

Aquatic Vascular Plants of New England: Part 3. Alismataceae.
C. B. Hellquist and G. E. Crow. Bull. No. 518. 1981.

Aquatic Vascular Plants of New England: Part 4. Juncaginaceae,
Scheuchzeriaceae, Butomaceae, Hydrocharitaceae. G. E. Crow
and C. B. Hellquist. Bull. No. 520. 1982.

Aquatic Vascular Plants of New England: Part 5. Araceae,
Lemnaceae, Xyridaceae, Eriocaulaceae, and Pontederiaceae.
C. B. Hellquist and G. E. Crow. Bull. No. 523. 1982.

Aquatic Vascular Plants of New England: Part 6. Trapaceae, Halora-
gaceae, Hippuridaceae. G. E. Crow and C. B. Hellquist. Bull. No.
524. 1983.

Hiker Traffic On and Near the Habitat of Robbins Cinquefoil, an
Endangered Plant Species. R. E. Graber and G. E. Crow. Bull. No.
522. 1982.

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