Selaginella densa var. standleyi (Maxon) Tryon

R. M. Tryon (1955) reported an elevation range of 1500--4660 m for Selaginella standleyi . I have not seen specimens from these lower and higher elevations.

Selaginella standleyi is a member of the S . densa complex. It has sometimes been confused with S . watsonii and S . sibirica ; it is, however, rather easy to distinguish by leaf and strobilus characters.

Plants terrestrial or on rock, forming cushionlike or rather short, loose mats. Stems decumbent to short-creeping, not readily fragmenting, irregularly forked, without budlike arrested branches, tips straight; main stem upperside and underside structurally slightly different, inconspicuously indeterminate, lateral branches radially symmetric, determinate, strongly ascending, 1-forked. Rhizophores borne on upperside of stems throughout stem length, 0.2--0.35 mm diam. Leaves monomorphic, in poorly defined pseudowhorls of 5 or 6, tightly appressed, ascending, green, linear, linear-oblong or linear-lanceolate, (2.5--)3--4.5 mm (smaller on upperside leaves and in ascending buds); abaxial ridges present; base decurrent, oblique, glabrous or rarely pubescent; margins short-ciliate to denticulate, cilia transparent, scattered, spreading to ascending, 0.05--0.07(--0.1) mm; apex keeled, obtuse, rather abruptly bristled; bristle usually yellowish or transparent to opaque, slightly puberulent or smooth, (0.4--)0.7--1.25 mm. Strobili solitary, 0.5--1(--2.3) cm; sporophylls deltate-ovate, rarely ovate-lanceolate, abaxial ridges well defined, base glabrous, margins short-ciliate to denticulate on distal 3/4, apex keeled, strongly truncate in profile, abruptly bristled.

Alta., B.C.; Alaska, Colo., Mont., Wyo.

Rock crevices, granitic outcrops, gravelly soil, bare soil, or alpine meadows; 2000--3700m.

Selaginella densa Rydberg var. standleyi (Maxon) R. M. Tryon

Selaginella standleyi là một loài dương xỉ trong họ Selaginellaceae. Loài này được Maxon mô tả khoa học đầu tiên năm 1920.