Nuphar polysepala Engelm (Engelm.) E.O. Beal
Rocky Mountain pond-lily (spatterdock; yellow pond-lily)
Nymphaeaceae (Water-lily family)

Introduction to Vascular Plants


© Brian Klinkenberg     (Photo ID #40648)


E-Flora BC Static Map

Distribution of Nuphar polysepala
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Species Information

Perennial aquatic herb from a thick large rhizome; stems thick, fleshy, submerged or emersed, 1-2 m long.
Floating or submerged, long-stalked, the stalks 1-2 m long, appearing alternate from the rhizome, blades heart-shaped, 10-40 cm long, 6-30 cm wide, leathery.
Inflorescence of solitary, large, waxy, floating flowers on long stalks arising from the rhizome; petals yellow (with reddish or greenish tinges), 10-20, smaller than the sepals and the numerous yellow or reddish-purple stamens; sepals usually 6 or 9, 2.5-6 cm long, the outer greenish and shorter than the inner yellow ones, thick.
Berry-like capsules, oval, leathery, rupturing irregularly; seeds numerous in a jelly-like seed mass, the seeds 4-5 mm long.
Two species occur in BC:

1. Sepals usually 6, 2.5-3.5 cm long; stamens yellow; seeds about 5 mm long................... N. variegata (Durand) Beal

1. Sepals usually 9, (3) 3.5-6 cm long; stamens reddish or purplish; seeds about 4 mm long................... N. polysepala (Engelm.) Beal

SourceThe Illustrated Flora of British Columbia


Ecological Framework for Nuphar polysepala

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres)
633 1 1735
Slope Gradient (%)
0 0 20

Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]

93 40 213
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
7 5 8
Modal Nutrient Regime
# of field plots
 species was recorded in:
Modal BEC Zone Class

All BEC Zones (# of stations/zone) species was recorded in

CDF(18), CWH(61), ESSF(3), ICH(12), IDF(2), MH(1), MS(4), PP(1), SBPS(10), SBS(6)

Habitat and Range

Ponds and slow-moving streams in the lowland, steppe and montane zones; ssp. polysepala - common in BC south of 55æ N, rare in NW BC; ssp. variegata - infrequent in E BC; ssp. polysepala - N to AK, YT and NT and S to SD, CO and CA, ssp. variegata - N to YT and NT, E to NF and S to DE, OH, NE, MT and N ID.

SourceThe Illustrated Flora of British Columbia


Synonyms and Alternate Names:
Nuphar lutea subsp. polysepala (Engelm.) E.O. Beal
Nuphar polysepalum
Nymphaea polysepala (Engelm.) Greene
Nymphozanthus polysepalus (Engelm.) Fernald