Flora of North America species comparison

radially symmetric, long-creeping, short-creeping, or pendent, not readily fragmenting, irregularly forked, without budlike arrested branches, tips straight;

main stem indeterminate, lateral branches determinate, spreading, 1–2-forked.

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.

monomorphic, in alternate pseudowhorls of 4 (on main stem and older lateral branches) or 3 (on young lateral branches and secondary branches), loosely appressed, ascending, green, linear to linear-lanceolate or narrowly triangular-lanceolate, (2–)2.5–3.4 × 0.45–0.5(–0.7) mm;

abaxial ridges prominent;

base mostly cuneate and decurrent, rarely rounded and adnate (on young branches), pubescent or glabrous;

margins entire to denticulate or very short-ciliate, cilia transparent, scattered, mostly ascending, dentiform toward apex, 0.02–0.07 mm;

apex keeled, slightly attenuate, short- to long-bristled;

bristle transparent greenish to greenish-yellowish, rarely white, smooth, seldom slightly puberulent, sometimes breaking off, 0.25–0.7(–1) mm.

dimorphic, not clearly ranked.

sometimes paired, 0.5–3.5 cm;

sporophylls lanceolate to ovate-lanceolate, abaxial ridges prominent, base glabrous, with prominent auricles (no other species has such prominent auricles), margins entire or very short-ciliate to denticulate, apex keeled, short- to long-bristled.

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.

borne on upperside of stems, throughout stem length, 0.15–0.27(–0.3) mm diam.

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

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.