Flora of North America species comparison

gray, cracked and irregularly fissured.

gray, cracked and irregularly fissured.

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

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

bright green to yellow-green, becoming yellow with age, not viscid, ridges between longitudinal grooves barely papillate, smooth;

internodes 1–5 cm.

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

internodes 3–10 cm.

opposite, 2–5 mm, connate to 1/2–3/4 their length, not photosynthetic;

bases thickened, brown, persistent, becoming hard, enlarged, and black;

apex setaceous.

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

bases becoming gray and shredded with age;

apex spinose.

2–several at node, obovoid, 5–7 mm, sessile;

bracts opposite, 6–10 pairs, light yellow and slightly reddened, ovate, 2–4 × 2–3 mm, membranous, slightly connate at base;

bracteoles slightly exceeding bracts;

sporangiophores 2–4 mm, 1/4–1/2 exserted, with 5–8 sessile to nearly sessile microsporangia.

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.

cones 2–several at node, obovoid, 6–10 mm, sessile or on short, scaly peduncles;

bracts opposite, 4–8 pairs, ovate, 4–7 × 2–4 mm, membranous or papery, with yellow center and base, margins entire.

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.

buds conic, 1–2 mm, apex obtuse.

buds spinelike, to 10 mm.

= 28.