Lycopodium somae Hayata, Icon. Pl. Formosan. 5: 255. 1915 ["somai"]; L. chinense Christ var. somae (Hayata) Masamune; L. selago Linnaeus var. somae (Hayata) Masamune; Urostachys somae (Hayata) Herter ex Nessel.

Plants terrestrial. Stem erect or ascending, 4-8 cm, 0.5-0.8 mm in diam. at middle, together with leaves 5-8 mm wide, 2-4 times dichotomously branched, upper portion often with bulbils. Leaves sparse, attached at right angles with stem, angled upward or reflexed, lustrous, narrowly elliptic, not contracted toward base, widest at middle, straight to bent at 180°, 2-4 mm, 0.5-0.7 mm wide at middle, papery, both surfaces glabrous, midrib indistinct, base truncate, decurrent, sessile, margin straight and not crispate, entire, apex acute. Sporophylls homomorphic with trophophylls; sporangia visible on both sides of sporophylls, yellowish, reniform.

The leaves of Huperzia somae are elliptic-lanceolate, widest at the middle, and contracted toward the base.

Banks of lakes, steep moss-covered slopes at roadsides, shaded places in forests; (600-)1600-2600(-3100) m. Taiwan [Japan, Philippines].