Selaginella austrotibetica X.C. Zhang, 2024

Zhang, Meng-Hua, Yang, Jie, Shalimov, Aleksandr Petrovich & Zhang, Jong-Soo Kang and Xian-Chun, 2024, Selaginella austrotibetica (Selaginellaceae), a new spikemoss from Xizang, China, Journal of Species Research 13 (1), pp. 1-9 : 5

Selaginella austrotibetica X.C. Zhang , sp. nov.

( Figs. 1A and 2 ) MfflṚffi (Zangnan Juanbai)

Type. CHINA, Xizang, Mêdog , on moss-covered rocky slope, 95.50°E, 29.66°N, altitude 2067 m, 22 December 2022, X. C . Zhang et al., 14089 (Holotype, PE!) .

Diagnosis. This new species is similar to S. sajanensis , such as creeping and slightly thick and shiny leaves, but distinct from it by having anisosporophylls, ventral and dorsal leaves that are ovate or broad-ovate, and an acute apex.

Description. Plant epilithic, seasonally green, shortly creeping. Rhizophores restricted to lower part of stem, borne on ventral side in axils of branches, 0.1 mm in diam., 2.5-3.0 mm in length. Main stems branched throughout, terete, not sulcate, glabrous, branchlets sparse. Axillary leaves on branches symmetrical or slightly asymmetrical, ovate, 1.1-1.5 × 0.6-0.7 mm, slightly carinate, base exauriculate, margin entire in basal half, upward slightly ciliolate. Dorsal leaves slightly ascending, asymmetrical, broad-ovate, 0.7-1.0 × 0.6-0.8 mm, slightly carinate, base obtuse to rounded, margin denticulate or very shortly sparsely ciliolate, not membranous, apex acute, the distance between upper and lower two adjacent dorsal leaves are about 2.0 mm. Ventral leaves slightly ascending, asymmetrical, ovate, 1.0-1.3 × 0.6-0.8 mm, margin almost entire or denticulate, apex acute, and the distance between the upper and lower two adjacent ventral leaves is about 1.0 mm. Strobili solitary, terminal; sporophylls slightly dimorphic, dorsal sporophylls asymmetrical, broad-ovate, 0.8-1.3 × 0.5-0.7 mm; ventral sporophylls ovate, 0.8- 1.3 × 0.5-0.7 mm. Sporangia only borne on the ventral sporophylls in the few already drying and incomplete strobili, only microsporangia are found, micorspores yellowish orange.

Distribution and habitat. Selaginella austrotibetica is known so far only from its type location in Mêdog County, Xizang, China, where it creeps on moss-covered rocky cliffs.

Etymology. The specific epithet ‘austrotibetica’ refers to its location at South Xizang.

Conservation status. Selaginella austrotibetica was found only in a small area with few individuals in Mêdog County, Xizang. Therefore, this species should be considered as Critical Endangered (CR), according to the IUCN Red List guidelines.

Figures

Fig. 1. Habitats of Selaginella austrotibetica and S. vaginata.A:S. austrotibetica collected from Xizang; B: S. vaginata collected from Yunnan.

Fig. 2. Morphology of Selaginella austrotibetica X. C. Zhang. A: Adaxial view of branchlet; B: Abaxial view of branchlet; C: Rhizophore on ventral side; D: Dorsal leaf; E: Ventral leaf; F: Axillary leaf; G: Strobilus(a portion).