UW Burke Herbarium species comparison

Leaves submersed, generally spirally arranged, sessile;

stipules inconspicuous, usually brown or uncommonly white, 0.2-2.2 cm, free from blade, fibrous and shredding at tip, veins persisting as fibers with age;

blade light to olive green, uncommonly tinged red, linear, not curved, 1.3-8.2 cm long and 0.3-2.3 mm broad, base somewhat tapering, basal lobes absent and not clasping, margins entire and not wavy, apex not hoodlike, acute to apiculate, uncommonly bristle-tipped, lacunae rarely present, when present 0-2 rows on each side of midrib, veins usually 1-3.

Inflorescence a capitate to cylindric interrupted spike, up to 7 mm, unbranched, above water;

peduncles emerging from axils of leaves nearest base, rarely from axils of distal leaves, curved backward, clavate, typically 0.3-1.1 cm.

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.

Drupes obovate to nearly orbicular, 1.4-1.7 mm long and 1.1-1.2 mm broad, light green; keeled beneath, 0.2 mm or less;

beak erect, 0.2 mm high or less.