Flora of North America species comparison

not proliferous.

not proliferous.

erect, unbranched;

scales black with lighter margins, linear-lanceolate, 3–6 × 0.4–0.8 mm, margins entire.

erect or ascending, usually unbranched;

scales dark brown throughout, narrowly deltate, 2–3 × (0.2–)0.5–1 mm, margins entire.

monomorphic.

monomorphic but fertile leaves generally larger than sterile leaves.

reddish brown throughout, lustrous, 1–12(–20) cm, 1/3–1/10 length of blade;

indument of black filiform scales.

reddish brown at base, becoming green distally, dull but sometimes lustrous at base, 0.5–12 cm, 0.1–1.5 times length of blade;

indument of dark brown, narrowly deltate scales at base, of minute, club-shaped hairs distally.

linear, 1-pinnate throughout, 5–25(–40) × 1–2.5(–3) cm, thick, glabrous;

base gradually tapered;

apex acute, not rooting.

highly variable in size and shape, even on 1 plant, narrowly deltate to linear-lanceolate, simple, 1–30 × 0.5–5 cm, leathery, sparsely pubescent, hairs more numerous abaxially than adaxially;

blade base cordate, auriculate, or occasionally hastate, auricles rarely attenuate and radicant;

margins entire to sinuate, rarely irregularly incised;

apex rounded to very long-attenuate and, if attenuate, generally rooting at tip.

in 10–40 pairs, oblong to quadrangular, somewhat asymmetric;

medial pinnae 4–15 × 2–5 mm;

base rounded to cuneate;

margins crenulate or ± entire;

apex obtuse.

free, obscure.

obscure, anastomosing to form areoles near midrib.

1(–3) per pinna, only on basiscopic side.

numerous, scattered somewhat irregularly over blade, often joined at vein junctures.

32 per sporangium.

64 per sporangium.

reddish brown throughout, lustrous, glabrous.

green, dull, nearly glabrous.

= 2n = 108 (apogamous).

= 72.