Home/Species/ Pygmy Water-lily

Nymphaea tetragona

Georgi

Pygmy Water-lily

G5Secure Found in 2 roadless areas NatureServe Explorer →

G5SecureGlobal Rank

Least concernIUCN

Identity

Unique IDELEMENT_GLOBAL.2.130338

Element CodePDNYM050B0

Record TypeSPECIES

ClassificationSpecies

Classification StatusStandard

Name CategoryVascular Plant

IUCNLeast concern

Endemicoccurs (regularly, as a native taxon) in multiple nations

KingdomPlantae

PhylumAnthophyta

ClassDicotyledoneae

OrderNymphaeales

FamilyNymphaeaceae

GenusNymphaea

Other Common Names

Northern Water-lily (EN) Nymphéa tétragonal (FR) pygmy waterlily (EN)

Concept Reference

Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

Taxonomic Comments

The true Nymphaea tetragona occurs in lower USA only in Washington state, where it was recorded in 1930; otherwise in Canada and Alaska. The true N. tetragona is also apparently rare in Sask., Man., Alta., BC. Remaining reports are N. leibergii (Mont., Idaho, Maine, Mich., Minn., not Alaska or Washington; also BC, Alta., east to Quebec), most common in Ontario. N. tetragona is also in Finland, former Soviet Union, China, Japan, etc.; common in Alaska.

Conservation Status

Rank MethodExpertise without calculation

Review Date2016-08-26

Change Date1984-06-11

Edition Date1995-05-22

Edition AuthorsK. Crowley, MRO

Range Extent20,000 to >2,500,000 square km (about 8000 to >1,000,000 square miles)

Number of Occurrences21 to >300

Rank Reasons

Nymphaea tetragona occurs locally and sporadically throughout a broad, circumpolar range.

Range Extent Comments

Nymphaea tetragona is a circumpolar species that occurs sporadically across northern North America and Eurasia. In North America, it occurs from northern Maine and Quebec west to British Columbia and Alaska. In the U.S., it occurs only in Maine, Michigan (Isle Royale), Minnesota, and Montana, and is historical in Idaho and Washington.

Occurrences Comments

Occurs at 22 sites in Minnesota, 2 in Michigan, 1 in Montana. Historical in Idaho and Washington. Information not available for Eurasia.

Threat Impact Comments

The primary threat to Nymphaea tetragona is a change in the water quality of its habitats. Threats include nearby logging, siltation, nutrient loading, and eutrophication. Also threatening is succession and competition with emergent vegetation.

Ecology & Habitat

Description

Pygmy Water-lily is an herbaceous perennial with submergent stems and floating leaves arising from a thick rhizome. The leaves have a long, slender petiole attached to the base of a long, v-shaped notch in the elliptic blades that are 7-10 cm long. The bowl-shaped flowers have long, slender stalks and float on the surface of the water. Each flower has 4 light green, narrowly elliptic sepals that are 2-3 cm long and 7-15 white, narrowly lance-shaped petals of the same length. There are 30-45 yellowish stamens, and the stigma is large and saucer-shaped. The fruit is woody and berry-like.

Diagnostic Characteristics

BRASENIA SCHREBERI does not have a notch in the leaves. NUPHAR has yellow flowers, and the lower leaf surface is not as purple as in NYMPHAEA. NYMPHAEA ODORATA has larger leaves, 20-30 petals, and 50-100 stamens.

Habitat

Nymphaea tetragona generally occurs in clear water, with a neutral or slightly alkaline pH, over a rich, organic substrate. Its habitats include ponds, shallow lakes, slow-moving streams, and edges of slow, open water channels through marshes. N. tetragona may also occur in streams impounded by beaver or by humans.

Other Nations (2)

CanadaN3

Province	Rank	Native
Manitoba	S2	Yes
British Columbia	S3	Yes
Northwest Territories	SNR	Yes
Yukon Territory	S1	Yes
Saskatchewan	S2	Yes
Alberta	S2	Yes

United StatesN5

Province	Rank	Native
Washington	SH	Yes
Idaho	SH	Yes
Alaska	S3	Yes
Rhode Island	SNR	Yes

Plant Characteristics

Economic Value (Genus)No

Roadless Areas (2)

Alaska (2)

Area	Forest	Acres
Castle	Tongass National Forest	49,289
Woewodski	Tongass National Forest	10,136

References (2)

Flora of North America Editorial Committee (FNA). 1997. Flora of North America north of Mexico. Vol. 3. Magnoliophyta: Magnoliidae and Hamamelidae. Oxford Univ. Press, New York. xxiii + 590 pp.
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.