UW Burke Herbarium species comparison

Various shades of red; submersed sessile, 2-8 x 1-2 cm, lanceolate to elliptic-oblong, tapered to both ends, entire, tip blunt, veins 7-9; floating 0 or short-petioled, lanceolate, base tapered, veins 7-15;

stipules beyond 3 cm, free, membranous, early-deciduous.

Leaves submersed, generally spirally arranged, sessile, fine to coarse;

stipules persistent, inconspicuous, convolute, blade 0.9-5.4 cm long and 0.2-2.5 mm broad, linear, not curved, base somewhat tapered, lobes absent and not clasping, margins entire and not wavy, apex subulate to obtuse, not hoodlike, lacunae in 1-5 rows on each side of midrib, veins usually 1-3.

Inflorescence an unbranched, capitate to cylindric spike, 1.5-10.1 mm, above or below water surface;

peduncles more than 3 per plant, terminal or emerging from axils, erect, uncommonly curved backward, cylindric to slightly clavate, more than 3 per plant.

Inflorescence generally < 3 cm, floating to emergent;

peduncle stiff.

Tepals 4, in 1 series;

stamens usually 4, with distinct anthers dehiscing vertically, pollen spheric;

pistils 1 or 4, usually lacking stipes but sometimes short-stipitate.

Around 2.5 mm, keels 1 or 3, generally, beaked, sides concave to convex.

Drupes ovoid with rounded sides, 1.5-2.2 mm long and 1.2-1.6 mm broad, uncommonly concave; not keeled;

beak erect, median, rarely near upper edge.