Plants terrestrial or epilithic, xerophytic, seasonally green, creeping, (5-)10-30 cm or more. Rhizophores at intervals throughout length of creeping stem and branches, borne on ventral side in axils of branches. Main stems branched throughout, reddish or brown, 0.36-0.74 mm in diam. in lower part, stem terete, not sulcate, glabrous; branches many, some basal lateral branches developing into rather long branch systems; primary leafy branches 5-8 pairs, 3 or 4 times pinnately branched, branchlets sparse, adjacent primary branches on main stem 2-4 cm apart, ultimate branches 0.7-1.9 mm wide including leaves. Axillary leaves on main stems larger than those on branches, narrowly oblong, base peltate, obtuse; axillary leaves on branches symmetrical, narrowly elliptic or narrowly oblong, 0.8-2.1 × 0.4-0.8 mm, margin lacerate-ciliolate. Dorsal leaves ± symmetrical, those on main stems slightly larger than those on branches; dorsal leaves on branches imbricate, rhomboid-ovate, 0.8-1.5 × 0.4-0.8 mm, carinate to strongly carinate, base oblique, peltate, margin subentire or lacerate-ciliolate, apex apiculate, parallel to axis. Ventral leaves asymmetrical, those on main stem larger than those on branches; ventral leaves on branches approximate, slightly ascending, oblong-obovate or obovate, 1-2 × 0.4-0.8 mm, basiscopic base decurrent, lacerate-ciliolate, acroscopic margin subentire, membranous, apex shortly aristate or apiculate. Strobili compact, tetragonal, terminal, solitary, 6-30(-80) × 1-1.5 mm; sporophylls similar to sterile leaves, monomorphic, broadly ovate, sharply carinate, not white-margined, margin slightly lacerate, apex acute; megasporophylls and microsporophylls at intervals, or megasporophylls on lower side; microsporangia suborbicular, rather thin, cells uniform; microspores yellowish orange or orange-red, megaspores pale yellow (sometimes 5 or 6 per sporangium, all 5 or 6 spores equal-sized, or 1 larger, or 4 larger).
Selaginella sanguinolenta is a very variable species; the leaves are sometimes subentire or entire in very dry conditions, and the leafy stem, as well as the branches with leaves, can then appear tetragonal.
S Gansu, Guizhou, Hebei, Heilongjiang, Hunan, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shanxi, Sichuan, Xinjiang, Xizang, Yunnan [Afghanistan, Himalaya, Kashmir, Mongolia, Nepal, Russia (Siberia)].
On rocks (limestone); 1400-3500 m.