UW Burke Herbarium species comparison

Submerged leaves linear, 5-20 mm. long, thin, 1-nerved, with a slight notch at the tip; floating and emergent leaves broadly spatulate, up to 4 mm. broad, 3-nerved.

Leaves all linear, 5-20 mm. long, 1-nerved, delicate, bright lustrous-green, inconspicuously white-margined, the tips bifid, the bases broadened but not forming ridges or wings on the stem between the bases.

Flowers imperfect, sessile in the leaf axils, each consisting of a single pistil or 1 stamen or both;

styles 2, distinct, 1-2.5 mm. long, deciduous;

floral bracts present.

Flowers imperfect, sessile in the leaf axils, each consisting of a single pistil or 1 stamen or both;

styles 1-2 mm. long, soon deciduous;

floral bracts wanting.

Carpels 2, oblong-obovate, about 1 mm. long and 0.7 mm. broad, with pit-like markings in vertical lines.

Carpels 1-2 mm. long, oval in outline, the margins narrowly winged above, the faces shallowly pitted.