Flora of North America species comparison

not proliferous.

proliferous.

erect, unbranched;

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

erect, unbranched;

scales brown throughout, linear-deltate, 1.2 × 0.1–0.3 mm, margins entire.

monomorphic.

monomorphic.

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

indument of black filiform scales.

green throughout, dull, 3–15(–20) cm, 1/3–2/3 length of blade;

indument absent.

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

base gradually tapered;

apex acute, not rooting.

deltate, 1-pinnate, 7–12(–20) × 3–6(–9) cm, thick, papery, glabrous;

base not tapered;

apex attenuate, not rooting.

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.

in 4–8 pairs, linear-lanceolate;

medial pinnae 30–70 × 7–15 mm, slightly curved, strongly excavated in proximal basiscopic 1/3;

base with small acroscopic auricle;

margins entire to dentate;

apex attenuate.

free, obscure.

free, obscure.

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

2–9 pairs, medial, commonly 1–2 less on basiscopic side than on acroscopic side.

32 per sporangium.

64 per sporangium.

reddish brown throughout, lustrous, glabrous.

green throughout, dull, glabrous.

= 2n = 108 (apogamous).

= 72.