7. Lycopodium clavatum Linnaeus, Sp. Pl. 2: 1101. 1753.
东北石松 dong bei shi song
Lycopodium aristatum Humboldt & Bonpland ex Willdenow var. robustius Greville & Hooker; L. clavatum var. asiaticum Ching; L. clavatum var. robustius (Greville & Hooker) Nakai.
Stolons subterranean, slender and creeping, 1 or 2 times forked, green, with sparse entire leaves; lateral branches erect, 20-25 cm tall, 3-5 times forked, sparse, flattened (young branches terete), stem together with leaves 9-12 mm in diam. Leaves spirally arranged, dense, angled upward, lanceolate, 4-6 × ca. 1 mm, leathery, with transparent hairs, midrib visible on both surfaces, base cuneate, decurrent, sessile, margin entire, apex acuminate. Strobili 2(or 3) together on a peduncle, peduncle up to 12 cm, bracts of peduncle spirally arranged, sparse, herbaceous, narrowly lanceolate; strobili erect, terete, 3.5-4.5 cm × ca. 4 mm, subsessile or with short, equally long pedicels; sporophyll broadly ovate, ca. 1.5 × 1.3 mm, papery, margin membranous, erose, apex acute, with short acute tip. Sporangia slightly exposed.
Coniferous forests, among dry moss; 700-1800 m. Heilongjiang, Jilin, Liaoning, Nei Mongol [Japan, Korea; North and South America].
Lycopodium clavatum differs from L. japonicum in its fertile branches each bearing 2(or 3) strobili with equal pedicels.