Selaginella helferi Warb.

Plants terrestrial, evergreen, scandent, 50-200 cm or more. Rhizophores restricted to lower part of stem or branched from lower to middle, with some spinelike protuberances at base. Main stems branched from lower part, pinnately branched, stramineous, 2.6-3.8 mm in diam. in lower part, subquadrangular or angulate, sulcate, glabrous or pubescent at axes; primary leafy branches 5-15 pairs, 3 times pinnately branched, branchlets regular, adjacent primary branches on main stem 5-16 cm apart, ultimate branches 5-8 mm wide including leaves. Axillary leaves on main stems obviously larger than those on branches, orbicular or reniform, ca. 3 × 2.8 mm, biauriculate at base (auricles smaller than those of Selaginella willdenowii); axillary leaves on branches ± symmetrical, ovate-lanceolate or oblong, 1.4-2.5 × 0.8-1.2 mm, base biauriculate, margin entire. Dorsal leaves asymmetrical, those on main stems obviously larger than those on branches; dorsal leaves on branches approximate, overlapping at leaf apex, falcate, 1.2-2.5 × 0.3-1 mm, not carinate, base oblique, not peltate, margin entire, apex cuspidate. Ventral leaves asymmetrical, those on main stem obviously larger than those on branches; ventral leaves on branches contiguous, spreading, oblong-falcate, 2.3-4.2 × 0.9-1.8 mm, apex acute or apiculate; basiscopic margin entire; acroscopic base with rounded auricle, not overlapping stem and branches, margin entire. Strobili solitary, terminal, compact, tetragonal, 5-14 × 1.6-3.4 mm; sporophylls uniform, white-margined, ovate-lanceolate, carinate, margin entire, apex acuminate; megasporophylls and microsporophylls at intervals or megasporophylls in middle on lower side of strobilus; microsporangia orbicular, rather thin, cells regular; microspores pale yellow, megaspores pale yellow.

It is a tropical plant. It grows in clearings in evergreen forests. It grows in moist places. In southern China it grows between 100-1,200 m above sea level. In Yunnan.