Flora of North America species comparison

alternate or whorled, rigid, angle of divergence about 30°.

opposite or whorled, rigid, angle of divergence about 30°.

pale green, becoming yellow, then gray with age, glaucous, with numerous very fine longitudinal grooves;

internodes 3–10 cm.

pale green, becoming yellow with age, not viscid, usually smooth or very slightly scabrous, with numerous longitudinal grooves;

internodes 1–5 cm.

in whorls of 3, 5–15 mm, connate to 1/2–3/4 their length;

bases becoming gray and shredded with age;

apex spinose.

opposite, 1–3 mm, connate to 1/2–3/4 their length;

bases membranous, brown, shredding and becoming gray with age, ± persistent;

apex obtuse.

1–several at node, obovoid, 6–10 mm, on short, scaly peduncles;

bracts in 8–12 whorls of 3, reddish brown, obovate, slightly clawed, 3–4 × 2–3 mm, membranous;

bracteoles nearly equaling bracts;

sporangiophores 4–5 mm, exserted to 1/4 their length, with 4–5 short-stalked microsporangia.

2–several at node, ellipsoid to obovoid, 4–8 mm, sessile;

bracts opposite, 4–8 pairs, light yellow, obovate, 2–3 × 2 mm, membranous, slightly connate at base;

bracteoles exceeding bracts;

sporangiophores 3–9 mm, 1/4–3/4 exserted, with 6–10 sessile to short-stalked (less than 1 mm) microsporangia.

cones 1–several at node, obovoid, 10–15 mm, on short, scaly peduncles (rarely sessile);

bracts in 6–9 whorls of 3, circular, 8–12 × 8–12 mm, papery, translucent with reddish brown center and base, base clawed, margins entire.

cones 2–several at node, obovoid to ellipsoid, 6–13 mm, sessile or on short peduncles;

bracts opposite, 4–7 pairs, elliptic, 3–7 × 2–4 mm, membranous with light brown to green, thickened center and base, slightly connate at base, margins entire.

buds spinelike, to 10 mm.

buds conic, 1–3 mm, apex obtuse.