Selaginella willdenowii (Desvaux ex Poiret) Baker

Plants terrestrial, evergreen, scandent, 100-200 cm or more. Rhizophores restricted to lower part of main stem or up to upper part, with some spinelike protuberances at base (as well as at axes of stems). Main stems branched from near base upward, stramineous or reddish, 2.4-3.5 mm in diam. in lower part, angulate, sulcate, glabrous; primary leafy branches 5-15 pairs, 3 times pinnately branched, ultimate branches simple or forked, branchlets sparse and regular, adjacent primary branches on main stem 6-13 cm apart, ultimate branches 3-7 mm wide including leaves. Axillary leaves on main stems obviously larger than those on branches, oblong, biauriculate (auricles larger than those of Selaginella helferi); axillary leaves on branches symmetrical, oblong or oblong-elliptic, 1.5-2.4 × 1-1.6 mm, base biauriculate, margin entire. Dorsal leaves asymmetrical, those on main stems obviously larger than those on branches; dorsal leaves on branches approximate to imbricate, overlapping at leaf apex, falcate, 0.9-1.4 × 0.4-0.6 mm, not carinate, base obliquely subcordate, margin entire, apex obtusely cuspidate. Ventral leaves asymmetrical, those on main stem obviously larger than those on branches; ventral leaves on branches slightly ascending or spreading, distant or approximate, oblong-falcate, 2.8-4 × 1-1.5 mm, margin entire, apex obtuse; acroscopic base with rounded auricle, not overlapping stem and branches. Strobili solitary, terminal, compact, tetragonal, 5-35 × 1.8-3.8 mm; sporophylls unlike sterile leaves, uniform, white-margined, suborbicular, margin entire, apex acute or cuspidate; megasporophylls in middle on lower side of strobilus; microsporangia orbicular, rather thin, cells regular; microspores pale yellow, megaspores whitish.