Friday, March 8, 2019

[Botany • 2019] Selaginella dianzhongensis (Selaginellaceae) • A New Spikemoss from Yunnan, China


Selaginella dianzhongensis X.C.Zhang

in Shalimov, Zhu, Zhang & Zhang, 2019. 

Abstract
A new species of spikemoss from Yunnan Province of China, Selaginella dianzhongensis, is described and illustrated based on evidence from gross morphology, micromorphology and molecular phylogeny. S. dianzhongensis is most similar to S. amblyphylla in its habit of creeping stem, leaf size, and obviously dimorphic sporophylls, but is distinct by its ventral leaves ovate-oblong, subcordate at base, basiscopic base entire, axillary leaves ovate and decurrent at base. Molecular phylogeny analysis of three chloroplast gene regions (rbcL, atpI, psbA) shows that S. dianzhongensis forms an independent branch with strong support which is distantly related to S. amblyphlla and S. kurzii, but sister to S. bodinieri which is quite different in habitat of erect or ascending stem and rhizophores restricted to the lower part, and slightly dimorphic sporophyllus.

Keywords: Lycophytes, Selaginella amblyphylla, taxonomy, Yunnan, rbcL, atpI, psbA


Figure 1. Selaginella dianzhongensis X.C.Zhang, sp. nov. A habit B adaxial view of strobilus C ventral leaf D axillary leaf E dorsal leaf F adaxial view of lower sporophyll G adaxial view of upper sporophyll H abaxial view of strobilus (Illustration made by Huixia Dong). 


Figure 2. Selaginella dianzhongensis X.C.Zhang, sp. nov. A individual B portion of plant C habit D dorsal leaf E ventral leaf F strobili G axillary leaf H proximal surface of megaspore I distal surface of megaspores J portion of megaspore surface enlarged to show infrastructural detail K distal surface of microspore L proximal surface of microspore M portion of microspore surface enlarged to show infrastructural detail surface (Taken from Yan-Mei Zhu 8158 (PE)).

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

Diagnosis: The new species resembles Selaginella amblyphylla in habit and gross morphology, but it is different in stems and branches reddish (vs. stramineous in S. amblyphylla), ventral leaves ovate-oblong, 1.1–2.2 × 0.4–0.8 mm (vs. oblong, 2–3 × 0.6–1.2 mm), base subcordate, basiscopic margin not ciliolate (vs. rounded and margin sparsely ciliolate); dorsal leaves oblique subcordate or cordate at base (vs. obliquely cordate), margin with rather long cilia (vs. denticulate or ciliolate); axillary leaves ovate and decurrent at base (vs. ovate or triangular and obtuse to decurrent at base); strobili 3.2–4.0 × 2.3–3.5 mm (vs. 3.5–10 × 3.2–4.4 mm), ventral sporophylls margin ciliolate, dorsal sporophylls margin denticulate (vs. both sporophylls margin ciliolate).
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Etymology: Dianzhong means central Yunnan in Chinese: the type locality (Yimen) is in the central Yunnan area which is centered on the Provincial capital city Kunming.

Distribution and habitat: Selaginella dianzhongensis is known only from Yimen county, Yunnan, growing on mossy soils in a mixed evergreen forest, at ca. 1576 m a.s.l. (Fig. 3).


 Aleksandr Petrovich Shalimov, Yan-Mei Zhu, Meng-Hua Zhang and Xian-Chun Zhang. 2019. Selaginella dianzhongensis (Selaginellaceae), A New Spikemoss from China. PhytoKeys. 118: 75-87. DOI: 10.3897/phytokeys.118.30375