Selaginella guihaia X.C.Zhang, 2017

Wu, Yu-Dong, Zhang, Hong-Rui & Zhang, Xian-Chun, 2017, Selaginella guihaia (Selaginellaceae): A new spikemoss species from southern China and northern Vietnam around the Gulf of Tonkin, PhytoKeys 80, pp. 41-52 : 41-43

Selaginella guihaia X.C.Zhang sp. nov. Figs 2 , 3 , 4

Diagnosis.

The new species is similar to S. doederleinii , S. ornata and S. trachyphylla in the habit and the morphology of dorsal leaves, ventral leaves, axillary leaves and sporophylls. However, S. guihaia can be easily recognized by its obvious white-margined leaves. The white-margin is about three cells wide in S. guihaia , but it is only one cell wide in S. doederleinii , S. ornata , and S. trachyphylla .

Type.

China, Guangxi: Pingxiang, Mt. Daqingshan , alt. 600m, 27 Aug 1986 , Beijing Youth Expedition 0980 (Holotype: PE![No. 1365103]) (Figure 3 ).

Description.

Terrestrial. Evergreen, suberect or ascending from decumbent base, 20-50 cm. Rhizophores branched from base to middle of main stem. Main stems pinnately branched from lower part upward, stramineous, 1.5-2 mm in diam. in lower part, oval or subquadrangular, glabrous; primary leafy branches 3-10 pairs, 2 or 3 pinnately branched, secondary branches once pinnately branched, tertiary branches forked, branchlets sparse, adjacent primary branches on main stem 1-6 cm apart, leafy portion of main stem including leaves 0.8-1.8 mm wide at middle, ultimate branches 3-6 mm wide including leaves. Axillary leaves on branches symmetrical, ovate, 0.9-1.7 × 1.7-3.7 mm, bases exauriculate, margins denticulate, obviously white-margined. Dorsal leaves on branches imbricate, ovate, 0.9-2.3 × 0.3-0.9 mm, carinate, base cuneate or obliquely subcordate, margins denticulate, obviously white-margined, apices acuminate to aristate, parallel to axis. Ventral leaves on branches contiguous or overlapping, slightly ascending, oblong-falcate, 2.1-4.4 × 0.8-1.9 mm, upper surfaces on lower scabrous halves of the laminae or also rarely scabrous on upper half; basiscopic base margin entire, margin subentire, denticulate at base; acroscopic base rounded, overlapping stem and branches, margin denticulate in basal half, obviously white-margined. Strobili solitary or in pairs, terminal, compact, tetragonal, 0.8-1.4 × 0.4-0.8 mm; sporophylls monomorphic, ovate-triangular, carinate, margins denticulate, obviously white-margined, apices acuminate; sporangia pale yellow to pale brown; megasporangia spherical; microsporangia elliptic-oblong, relatively thick, marginal cells differentiated; megaspores whitish, microspores pale yellow.

Specimens examined.

China. Guangxi: Ningming, 31 Dec 2015, X.C.Zhang & al.7879 (PE); Ningming, 1 Jan 2016, X.C.Zhang & al. 7886 (PE), X.C.Zhang & al. 7887 (PE), X.C.Zhang & al. 7899 (PE), X.C.Zhang & al. 7900 (PE); Shangsi , 17 Sep 2009, Mt. Shiwandashan , 600 m, R.H.Jiang 059 (PE); Shangsi, Mt. Shiwandasahn 10 Jun 2009, 380m, S.Y. Dong 2932 (IBSC); Fangchenggang, Fulong Village , Mt. Pinglong , 360 m, 19 Sep 2009, R.H. Jiang 145 (PE); Fangchenggang, Nale Village , 250 m, 20 Sep 2009, R.H.Jiang 174 (PE); Shangsi, 22 Sep 2009, Mt. Shiwandashan , 680 m, R.H.Jiang 220 (PE); Fusui, Lucheng, 200-370 m, 26 Apr 1957, S.Q. Chen 12074 (PE); Shang-sze (= Shangsi), Shap Man Taai Shan (= Mt. Shiwandashan ), 11-30 Jul 1934, W.T.Tsang 23870 (BM) ; Hainan: Baisha, Yinggeling , 1000 m, 27 Aug 2005, S.Y.Dong 1450 1464 (PE) . Vietnam: Tien-yen, Kau Nga Shan and Vicinity , 23-30 Sep 1940, W.T.Tsang 30553 (PE); Chuk-phai, Ha-coi, Taai Wong Mo Shan and Vicinity, W.T.Tsang 29052 (P); Dam-ha, Sai wong Mo Shan, 18 Jul - 9 Sep 1940, W.T.Tsang 30273 (P); Tien-yen, Kau Nga Shan and Vicinity, 23 Sep - 7 Oct. 1940, W.T.Tsang 30582 (P); Chuk-phai, Ha-coi, Taai Wong Mo Shan and Vicinity, 18 Nov - 2 Dec 1936, W.T.Tsang 27196 (P); Tonkin, Kau Nga Shan and vicinity, Sept. 23 - Oct. 7. 1940, W.T.Tsang 30582 (B) .

Distribution and ecology.

Widely distributed in southern China (Guangxi and Hainan) and northern Vietnam around the Gulf of Tonkin (Beibu Gulf), growing in evergreen broad-leaved forests at 250 to 1000 m a.s.l. (Figures 4 , 5 ).

Etymology.

The specific epithet " guihaia " alludes to the ancient Chinese name for the remote geographic region where the species occurs.

Conservation status.

We evaluated the conservation status of Selaginella guihaia according to the IUCN (2012) criteria for risk assessment: S. guihaia falls into the Least Concern (LC) category. S. guihaia is in fact known from many localities from southern China and northern Vietnam around the Gulf of Tonkin.

Figures

Figure 2. Selaginella guihaia X. C. Zhang A Habit B Dorsal leaf C Ventral leaf D Part of main stem showing ventral leaves, dorsal leaves, and strobili E Part of main stem showing ventral leaves, axillary leaves, and strobili F Megasporophyll G Microsporophyll (Drawn by C. Z. Ji from Beijing Youth Expedition 0980, PE).

Figure 3. Type of Selaginella guihaia X. C. Zhang, sp. nov. (PE).

Figure 4. Selaginella guihaia X. C. Zhang, sp. nov. A Dorsal view of branch B Ventral view of branch. C Strobilus D Rhizophore E Habit.

Figure 5. Distribution map of Selaginella guihaia X. C. Zhang, sp. nov.