Flora of North America species comparison

and stolons absent.

sometimes in 2s, spreading, linear to narrowly elliptic, 4.7–24.8 × (0.8–)1.8–4.3 mm, flat.

cauline, whorled, 3–7 at each node, or leaves opposite at 4+ proximalmost nodes, submersed, sessile;

blade linear to linear-lanceolate, apex acute;

midvein without lacunae along side(s), blade uniform in color throughout;;

abaxial surfacely without prickles or aerenchyma;

intravaginal squamules entire.

staminate spathes cylindric, 10.2–42 mm;

peduncles abscissing following anthesis; pistillate spathes linear, 9–67 mm.

solitary, sessile;

spathes not winged.

unisexual; staminate flowers: stamens 7–9;

pedicels remaining briefly following anthesis;

inner 3 filaments connate proximally, forming column;

anthers 3–4.5 mm;

pollen in monads; pistillate flowers: styles 2.3–3 mm.

unisexual, staminate and pistillate on different plants, or rarely bisexual, usually projected to surface of water by elongate floral tube base, sessile;

petals white.

filaments distinct or 3 inner connate ½ their length;

anthers oval;

pollen in monads or tetrads.

ovary 1-locular;

styles 3, not 2-fid.

ovoid to lance-ellipsoid, smooth, dehiscing irregularly.

ellipsoid, 2.8–3 mm, densely covered with long hairs.

cylindric to fusiform, glabrous to hirsute.

stems rooted in substrate, branched or unbranched, elongate.