Flora of North America species comparison

short-creeping, branched, branches 1–2-forked, flat, not articulate, glabrous.

radially symmetric, underground (rhizomatous) and aerial, not readily fragmenting, irregularly forked; rhizomatous and aerial stems often with 1 branch arrested, budlike, tips straight;

aerial stems mainly erect, seldom ascending, with budlike arrested branches throughout stem length.

papery, delicate.

dimorphic, not clearly ranked.

solitary or paired, lax, flattened, 1–4 cm;

sporophylls ovate to ovate-deltate, strongly keeled, keel dentate, base glabrous, slightly cordate to rounded, margins serrate, apex acuminate;

megasporophylls larger and wider than microsporophylls, usually on underside of strobili.

solitary, 0.5–1.2(–2.5) cm;

sporophylls deltate-ovate to ovate-lanceolate, abaxial ridges prominent, base glabrous, margins denticulate, apex acute to obtuse.

throughout stem length, 0.06–0.1 mm diam.

borne on upperside of stems, restricted to rhizomatous stems and lower 1/4 of aerial stems, 0.16–0.3 mm diam.

leaves nearly perpendicular to stem, green, ovate to ovate-elliptic, 1–2 × 0.5–1.3 mm;

base rounded to slightly subcordate;

margins slightly transparent, serrate;

apex acute.

leaves ovate to ovate-lanceolate or lanceolate, 1–1.8 × 0.4–0.8 mm;

base rounded to oblique;

margins green, serrate;

apex abruptly tapered, long-acuminate to bristled, frequently transparent, midrib extending into apex.

stem leaves loosely appressed, straight, scalelike.

stem leaves appressed, ascending, green, linear-lanceolate to narrowly lanceolate, 1.8–2.1 × 0.49–0.56 mm;

abaxial ridges prominent;

base cuneate and decurrent to slightly rounded and adnate, glabrous;

margins denticulate to very short-ciliate, cilia transparent, spreading to ascending toward apex, 0.02–0.04 mm;

apex acute or seldom blunt.