Flora of North America species comparison

somewhat elongate, 3–5 × 2–4 mm;

teeth 8–18, narrow, 1.5–4 mm, centers dark and margins white.

dimorphic;

vegetative stems green, branched, 16–50 cm;

hollow center 1/6–1/3 stem diam.

brown, with stomates, initially unbranched, persisting and becoming branched and green after spore discharge.

in regular whorls, horizontal to drooping, solid;

ridges 3;

valleys channeled; 1st internode of each branch equal to or longer than subtending stem sheath;

sheath teeth deltate.

small, whorled, fused into sheaths;

tips remaining free, toothlike.

borne on peltate sporophylls aggregated in cones 0.3–10 cm.

green (except white in hybrids), all 1 kind.

green, terrestrial, unisexual;

male gametophytes smaller than female.