Flora of North America species comparison

elongate, 4–9 × 2–5 mm;

teeth dark, 5–10, narrow, 2–5 mm, margins white, scarious.

squarish in face view, 3–6 × 2.5–6 mm;

teeth reddish, 8–18, papery, 3–10 mm, coherent in 3–4 large groups.

monomorphic, green, branched or unbranched, 20–80 cm;

hollow center small, to 1/3 stem diam.;

vallecular canals nearly as large.

dimorphic;

vegetative stems brownish to green, branched, 25–70 cm;

hollow center 1/6–1/3 stem diam.

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

when present only from midstem nodes, spreading, hollow;

ridges 4–6;

valleys rounded; 1st internode of each branch shorter than subtending stem sheath;

sheath teeth narrow.

in regular whorls, delicate, arching, branched, solid;

ridges 3–4;

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

sheath teeth attenuate.

=216.

=216.