Flora of North America species comparison

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

alternate (rarely whorled), lax, angle of divergence about 55°.

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

internodes 3–10 cm.

gray-green, becoming green, then yellow-green with age, glaucous, with several moderately deep longitudinal grooves;

internodes 1–8 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 2/3–7/8 their length;

bases splitting at margins, 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.

1–2 at node, lanceoloid, 4–8 mm, sessile or on short to long, smooth peduncles;

bracts opposite, 6–12 pairs, light yellow to reddish, obovate, 2–4 × 2–3 mm, membranous, free or slightly connate at base;

bracteoles barely exceeding bracts;

sporangiophores 3–5 mm, exserted to 1/2 their length, with 4–6 long-stalked (1–2 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 1–2 at node, ovoid, 6–10 mm, on short to long, smooth peduncles;

bracts opposite, 3–6 pairs, 3–4 × 2–3 mm, ovate, connate to 1/8–7/8 their length, inner pairs becoming succulent and red when ripe.

buds spinelike, to 10 mm.

buds attenuate, 1–3 mm.