笔直石松 bi zhi shi song

Type: China. Sichuan: Leibo County, Xining, Wayaoping, on rock under bushes, 3 Aug 1978, Xian-Xu Kong (H. S. Kung) 5642 (holotype, CDBI-302; isotype, CDBI-303).

Lycopodium verticale is most similar to L. obscurum but differs by its lateral branches mostly angled upward and its whole branches forming a terete shape.

Stolons subterranean, slender and creeping, brownish yellow, glabrous or with few leaves; lateral branches ascending, 15-50 cm tall, lower part not branched, distal part forked; branches dense, whole branches forming a terete shape. Leaves spirally arranged, slightly sparse, ascending or nearly spreading, linear-lanceolate, 3-4 × ca. 0.6 mm, leathery, midrib slightly conspicuous, base cuneate, decurrent, sessile, margin entire, apex acuminate, with short acute tip. Strobili solitary, terminal on branchlets, erect, terete, sessile, 2-3 cm × 4-5 mm; sporophylls broadly ovate, ca. 3 × 2 mm, papery, margin membranous, with erose teeth, apex acute. Sporangia borne in axils of sporophylls, enclosed.

Among grasses, under shrubs in coniferous and broad-leaved mixed forests, wet places on cliffs; 1000-3000 m. Anhui, Chongqing, Guizhou, Hubei, Hunan, Jiangxi, Shaanxi (Qin Ling), Shanxi, Sichuan, Taiwan, E Xizang, NE Yunnan, Zhejiang [Japan].

The treatment of this taxon has been controversial; some treat it as a variety, some as a form (Lycopodium dendroideum Michaux f. strictum Milde, Fil. Europ. 254. 1867; L. obscurum f. strictum (Milde) Nakai ex H. Hara), while others do not recognize it at all. Compared with L. obscurum, it is smaller with erect branches, and it occurs in different regions. It is better to be treated as a species.

A similar European species, Lycopodium juniperoideum Swartz, does not occur in China. The relationships among L. juniperoideum, L. obscurum, and L. verticale are unclear.