Selaginella monospora

Plants terrestrial, evergreen, long creeping, 35-85 cm or more. Rhizophores at intervals throughout length of main stem, borne on ventral side in axils of branches. Main stems branched throughout, pinnately branched, stramineous, 1.5-2 mm in diam. in lower part, stem oval or terete, not sulcate, branches many, some primary lateral branches developed into long branch systems; primary leafy branches 8-12 pairs, once or twice pinnately branched or 2 or 3 times forked, tertiary branches forked, branchlets dense and regular, adjacent primary branches on main stem 2.5-5.5 cm apart; leafy portion of main stem including leaves (5-)8-11 mm wide at middle, ultimate branches 4-8 mm wide including leaves. Axillary leaves on main stems larger than those on branches, ovate or broadly ovate, base not peltate, obtuse; axillary leaves on branches asymmetrical, ovate, narrowly ovate, or narrowly elliptic, 2-3 × 0.8-1.6 mm, base exauriculate, margin denticulate. Dorsal leaves asymmetrical, those on main stems slightly larger than those on branches, margin denticulate or subentire in ultimate branches, base obtuse, apex shortly aristate; dorsal leaves on branches contiguous, ovate-lanceolate or elliptic, 1-1.6 × 0.3-0.7 mm, carinate or strongly carinate, base obtuse, not peltate, margin denticulate, apex acuminate or shortly aristate. Ventral leaves asymmetrical, those on main stem obviously larger than those on branches, 3.5-5.5 × 1.4-2.3 mm; ventral leaves on branches approximate, slightly ascending or spreading, ovate-triangular or oblong-falcate, 2.6-4.3 × 0.9-1.4 mm, apex subacute; basiscopic base decurrent, margin subentire or entire; acroscopic base enlarged, broader, strongly overlapping stem and branches, margin denticulate. Strobili solitary, terminal, compact, dorsiventrally complanate (sometimes appearing uniform), 3-20 × 1.9-3.2 mm; sporophylls slightly dimorphic, resupinate, not white-margined; dorsal sporophylls lanceolate, sharply carinate, margin minutely denticulate, apex acuminate, with sporophyll-pteryx complete and denticulate; ventral sporophylls ovate-lanceolate, carinate, base dilated, margin denticulate; strobili with megasporophylls in basal portion on lower side of strobilus, or megasporophylls and microsporophylls at intervals, or only 1 megasporophyll at base on lower side, elsewhere with microsporophylls; microsporangia transversely elliptic, rather thin, upper margin cells differentiated; microspores yellowish orange or pale yellow, megaspores whitish.