Flora of North America species comparison

proliferous.

not proliferous.

horizontal, often arching upward, unbranched (although clusters of stems often form from root proliferations, giving false appearance of single much-branched stem);

scales dark brown throughout, narrowly deltate, 2–4 × 0.2–0.4 mm, margins entire.

erect or ascending, rarely branched;

scales black throughout, linear-lanceolate, 2–3 × 0.2–0.4 mm, margin entire, apex attenuate.

monomorphic.

monomorphic.

dark brown to purplish black, lustrous proximally, fading to green distally, 2–11 cm, 1/2–1 1/2 length of blade;

indument of blackish, narrowly lanceolate scales only at very base and of minute hairs.

black or purplish black throughout, lustrous, 0.3–5 cm, 1/4–1/15 length of blade;

indument of black filiform scales at base.

deltate to lanceolate, 1–2-pinnate-pinnatifid, 2–11 × 1–7(–10) cm, thick, essentially glabrous;

base truncate or obtuse;

apex acuminate to acute, not rooting.

linear or narrowly oblanceolate, 1-pinnate throughout, 6–22(–37) × 1–1.8(–2.3) cm, thin, glabrous;

base tapered;

apex acute, not rooting.

in 4–10 pairs, deltate to lanceolate;

proximal (longest) pinnae 6–35 × 4–20 mm;

base obtuse to acute;

margins coarsely incised;

apex acute to rounded.

in 15–40 pairs, oblong;

medial pinnae somewhat asymmetric, oblong, 4–10 × 2–4(–5) mm;

base acute, acroscopically enlarged;

margins serrate to crenate, lobed;

apex obtuse.

free, obscure.

free, evident.

1–15 per pinna, on both basiscopic and acroscopic sides.

3–6 pairs per pinna, on both basiscopic and acroscopic sides of pinnae.

64 per sporangium.

64 per sporangium.

green throughout, dull, sparsely pubescent.

black throughout, lustrous, glabrous.

= 72.

= 144, 216.