Selaginella asprella Maxon

Selaginella asprella may be confused with S . leucobryoides particularly because of its readily fragmenting stems.

Plants on rock or terrestrial, forming cushionlike or loose mats. Stems decumbent to short-creeping, dry stem readily fragmenting, irregularly forking, without budlike arrested branches, tips straight; main stem upperside and underside structurally slightly different, inconspicuously indeterminate, lateral branches radially symmetric, determinate or not, often strongly ascending on cushionlike mats, 1--2-forked. Rhizophores borne on upperside of stems, throughout stem length, 0.2--0.4 mm diam. Leaves monomorphic, in alternate pseudowhorls of 4, tightly appressed, ascending, green, narrowly triangular-lanceolate to linear-lanceolate, (2--)2.5--4 X 0.45--0.7(--0.8) mm (smaller on young buds); abaxial ridges present; base cuneate and decurrent or sometimes rounded and adnate on young buds, pubescent (hairs often covering 1/4 of leaf length abaxially); margins ciliate, cilia transparent to whitish, spreading, 0.7--0.15 mm; apex keeled, attenuate or obtuse, bristled; bristle white or transparent, puberulent, 0.5--1.4 mm. Strobili solitary, 0.4--1.5(--2) cm; sporophylls lanceolate and strongly tapering to apex or deltate-ovate to ovate-lanceolate, abaxial ridges moderately defined, base pubescent or glabrous, margins short-ciliate to dentate, apex keeled or plane, bristled.

Calif.; Mexico in Baja California.

Limestone ridges, dry rocky slopes, igneous rock, exposed cliffs or gravelly soil; of conservation concern; 900--2700m.

Selaginella asprella is a species of spikemoss known by the common name bluish spikemoss. It is native to California and Baja California, where it has a disjunct distribution, occurring in the Klamath Mountains and mountain ranges several hundred miles to the south. It grows in rocky mountainous habitat, on cliffs of limestone rock substrate, and on forest ridges. This lycophyte grows in flat mats with many short, forking stems twisted together. The stems fragment easily, especially as they dry. The lance-shaped green leaves are up to 5 or 6 millimeters long, including the soft bristles at their tips. The leaves are alike in shape and borne in squarish whorls of four about the stem. They are flattened to the stem.

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