Flora of North America species comparison

elongate, 4–9 × 2–5 mm;

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

black or black-girdled and white distally, appressed, elongate, 3.5–8 × 2–5.5 mm;

teeth 7–16, centers dark, margins white, prominent, not articulate, tip usually brown, long, filiform.

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

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

vallecular canals nearly as large.

persisting more than a year, unbranched, 20–86 cm;

lines of stomates single;

ridges 7–16.

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.

apex pointed;

spores white, misshapen.

=216.