Rhizomes unbranched, erect, cylindric; stolons absent. Leaves: petiole glabrous. Leaf blade abaxially green to deep purple, adaxially green, ovate to elliptic, 3-19 × 2-15 cm, margins entire; venation radiate centrally, without weblike pattern, principal veins 7-13; surfaces glabrous. Flowers floating, 3-7.5 cm diam., opening and closing diurnally, only sepals and outermost (occasionally innermost) petals in distinct whorls of 4; sepals uniformly green, obscurely veined, lines of insertion on receptacle not prominent; petals 8-15, white; stamens 20-40, yellow, connective appendage projecting less than 0.2 mm beyond anther; filaments widest above middle, much longer than anthers; pistil 5-12-locular, appendages at margin of stigmatic disk tapered or slightly boat-shaped, 0.6-1.5 × 0.8-1.4 mm. Seeds ovoid, ca. 2-3 × 1.5-2 mm, ca. 1.3-1.5 times as long as broad, lacking papillae on surface.
Phenology: Flowering summer.
Habitat: Ponds, lakes, and quiet streams
Elevation: 0-1000 m
Alta., B.C., Man., Ont., Que., Sask., Idaho, Maine, Mich., Minn., Mont.
Although widely distributed in northern North America, Nymphaea leibergii is apparently not common in much of its range. It is closely related to N. tetragona (see also), with which it has been confused; it differs in a number of floral and foliar characteristics. Although the two species are sympatric over central and western Canada, the distinctions are maintained. Coexistent populations are unknown at this time; such populations would provide useful study opportunities and should be sought in the area of overlap, especially in southeastern and central Manitoba and east-central British Columbia where nearby populations exist.
A presumed natural hybrid between Nymphaea leibergii and N. odorata subsp. odorata has recently been found by Hellquist in northern Maine. It is intermediate in morphology between the two parental species and appears to be sterile.