Flora of North America species comparison

gray, cracked and irregularly fissured.

gray, cracked and fissured.

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

opposite 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 to dark green, becoming yellow with age, not viscid, slightly to strongly scabrous, with numerous longitudinal grooves;

internodes 1–6 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.

opposite (rarely in whorls of 3), 1–3(–5) mm, connate to 1/2–7/8 their length;

bases thickened, brown, shredding with age, ± persistent;

apex obtuse.

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.

2 (rarely 1 or whorled) at node, obovoid, 4–7 mm, sessile or rarely on short peduncles;

bracts opposite, 6–10 pairs, yellow to red-brown, obovate, 3–4 × 2–3 mm, membranous;

bracteoles slightly exceeding bracts;

sporangiophores 4–5 mm, 1/2 exserted, with 4–6 sessile to short-stalked (less than 1 mm) 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 usually 2 at node, ovoid, 6–10 mm, sessile or on short, scaly peduncles;

bracts opposite, 5–7 pairs, circular, 4–7 × 2–4 mm, membranous, with red-brown thickened center and base, margins entire.;

seed 1, ellipsoid, 5–8 × 2–4 mm, light brown to brown, smooth to slightly scabrous.

buds conic, 1–2 mm, apex obtuse.

buds conic, 1–2 mm, apex obtuse.

= 28.