Lycopodium casuarinoides Spring, Monogr. Lycopod. 1: 94. 1842; Lepidotis casuarinoides (Spring) Rothmaler.

Plants large, terrestrial. Rhizome long and creeping, aerial shoots woody and vinelike, up to several meters, terete, ca. 2 mm in diam., with sparse leaves; leaves spirally arranged, adnate, ovate-lanceolate to subulate, 1.5-3 × ca. 0.5 mm, base raised, arc-shaped, sessile, apex acuminate, with 1 membranous long awn 2-5 mm, sometimes awns deciduous. Sterile branches soft, yellowish green, terete, together with leaves ca. 4 mm wide, dichotomously branched with well-differentiated lateral branchlets much branched; leaves spirally arranged, but leaf base twisted and making branchlets complanate, dense, ascending, not lustrous, subulate, angled upward, 2-3 × ca. 0.5 mm, abaxially arc-shaped, concave adaxially, midrib indistinct, herbaceous, base decurrent, sessile, margin entire, apex acuminate, long aristate. Fertile branches soft, reddish brown, branchlets flattened, dichotomously branched with well-differentiated lateral branchlets; leaves spirally arranged, sparse, appressed, scalelike, ca. 0.8 × 0.3 mm, base decurrent, sessile, margin entire, apex acuminate, aristate; bracts similar to leaves on aerial shoots but smaller; strobili 6-26 per peduncle and terminal on multi-dichotomously branched peduncles forming a cone shape, with erect peduncles and pedicels, bent, reddish brown, 1-4 cm × 2-3 mm; sporophylls broadly ovate, imbricate, 2-3 × ca. 1.5 mm, thickly membranous, with irregular teeth on margin, apex acute, with membranous long awn. Sporangia borne in axils of sporophylls, enclosed, yellow, reniform.

Forests, forest margins, shrubs, riverbanks; 100-3100 m. Chongqing, Fujian, Guangdong, Guangxi, Guizhou, Hubei, Hunan, Jiangxi, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [tropical and subtropical regions of Asia: Bhutan, India, Japan, Nepal, and SE Asia extending to Papua New Guinea].