Selaginella wuyishanensis K.W.Xu, X.M.Zhou & Y.F.Duan, 2022

Xu, Ke-Wang, Chen, Shui-Fei, Song, Qiang, Zheng, Xiao, Li, Meng, Fang, Yan-Ming, Wei, Hong-Jin, Ding, Hui, Zhou, Xin-Mao & Duan, Yi-Fan, 2022, Selaginella wuyishanensis (sect. Tetragonostachyae, Selaginellaceae), a new species from East China and its phylogenetic position based on molecular data, PhytoKeys 202, pp. 107-119 : 107

Selaginella wuyishanensis K.W.Xu, X.M.Zhou & Y.F.Duan sp. nov.

Figs 2 , 3

Type.

China. Fujian: Wuyishan City, Mt. Wuyishan , alt. 200m, 27°41'12.82"N, 117°56'12.24"E, 25 Nov. 2021, Ke-Wang Xu et al. WY21 (holotype: NF!; isotype: PYU!) .

Diagnosis.

The new species is most similar to Selaginella albociliata and S. lutchuensis in the habit, sterile leaves, and spores. However, S. wuyishanensis can be distinguished from the latter two species by its long leaf cilia (up to 0.6 mm), ovate ventral sporophylls, and the smooth perispore surface of the megaspores (Figs 2 , 3 ).

Description.

Plants epilithic, evergreen, creeping, without erect or ascending stems. Rhizophores present at intervals throughout the length of creeping stem and branches, born on ventral side in the axil of main branches, slender, glabrous, 2-5 cm long, 0.1-0.2 mm in diameter; roots usually forked at the apex. Stem 5-12 cm long, rarely longer than 12 cm, 3-4 mm in width, irregularly and slightly dichotomously branched. Leaves arranged in four ranks (two dorsal and two ventral). Axillary leaves present at branching points, oblong-ovate, base slightly cuneate, apex acuminate, 0.8-1.2 × 2.2-2.5 mm, long ciliate along the margin from base to 2/3 of the axillary leaves, cilia up to 0.8 mm long. Ventral leaves asymmetrical, those on main stem similar to those on branches, imbricate on stem and branch throughout, ovate, 1.5-2.8 × 0.8-1.2 mm, apex slightly acute to acuminate, acroscopic base rounded, basiscopic base slightly cuneate, margin conspicuously white-margins; acroscopic margins ciliate at the base, cilia up to 0.6 mm long, basiscopic margins nearly entire at the base, ciliate or denticulate upward. Dorsal leaves symmetrical, ovate to oval, 0.8-1.6 × 0.6-0.9 mm, base rounded, apex aristiform, often reflexed, margins conspicuously white-callous, acroscopic margins sparsely ciliate, cilia up to 0.5 mm long, basiscopic margins ciliate, cilia short, no more than 0.1 mm long. Strobili usually in pairs or rarely three on the branches, terminal, resupinate, 1-2 cm long, megasporangia usually present at basal sporophylls and microsporangia present at upper ones; dorsal sporophylls ovate-lanceolate, base nearly rounded, apex acuminate, 1.2-1.8 × 0.4-0.8 mm, margin conspicuously white-callous, ciliate along the margin of basal part, cilia short; ventral sporophylls membranous, ovate-lanceolate, base rounded, apex caudate, ca. 0.6 × 1.3 mm, ciliate along the margin, cilia ca. 0.3 mm long. Megaspores yellow, trilete, oblate spheroid to subglobose, equatorial diameter 240-260 μm; perispore reticulate ornamentation with fine muri. Microspores reddish orange, trilete, hemispheric, equatorial diameter 35-42 μm; verrucate ornamentation of microspore covered with dense rodlets.

Distribution and habitat.

Selaginella wuyishanensis is known only from Fujian Province, East China. Three populations were observed to grow on rocks of the Danxia landform in evergreen broad-leaved forests at elevations of ca. 200-800 m.

Additional specimens examined.

China. Fujian: Wuyishan City, Mt. Wuyishan, alt. 327 m, 27°41'12.82"N, 117°56'12.24"E, 25 Nov. 2021, Ke-Wang Xu et al. WY521 (NF); the same locality, alt. 280 m, 27°39'17"N, 117°57'50"E, 27 Nov. 2021, Ke-Wang Xu et al. WY596 (NF); the same locality, Ke-Wang Xu et al. WY597 (NF); the same locality, Ke-Wang Xu et al. WY598 (NF); Yongan City, Tianbaoyan National Nature Reserve , 25°57'11"N, 117°33'14"E, 1 Nov. 2020, Wei & Chen JSL7744A (CSH) .

Etymology.

The species epithet is based on the name of the famous mount Wuyishan, referring to the type locality of the new species.

Figures

Figure 2. Selaginella wuyishanensis A, B habit C abaxial view of portion of branch D portion of branch showing the dorsal leaves E portion of branch showing the ventral and axillary leaves F, G strobili H axillary leave I axillary leave J dorsal leave K ventral sporophyll L dorsal sporophyll M proximal surface of megaspores N detail of megaspore surface O microscopic structures of microspore surface P proximal surface of microspore.

Figure 3. Illustration of Selaginella wuyishanensis A habit B adaxial view of branch C abaxial view of branch with rhizophore D axillary leaf E ventral leaf F dorsal leaf G strobili H ventral sporophyll I dorsal sporophyll (A-F drawn by Sun YB based on the isotype at NF G-I drawn by Wei HJ based on the paratype at CSH).