Research Article |
Corresponding author: Hui Ding ( nldinghui@sina.com ) Corresponding author: Xin-Mao Zhou ( xinmao.zhou@ynu.edu.cn ) Corresponding author: Yi-Fan Duan ( yifanduan@njfu.edu.cn ) Academic editor: Angelo Troia
© 2022 Ke-Wang Xu, Shui-Fei Chen, Qiang Song, Xiao Zheng, Meng Li, Yan-Ming Fang, Hong-Jin Wei, Hui Ding, Xin-Mao Zhou, Yi-Fan Duan.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Xu K-W, Chen S-F, Song Q, Zheng X, Li M, Fang Y-M, Wei H-J, Ding H, Zhou X-M, Duan Y-F (2022) Selaginella wuyishanensis (sect. Tetragonostachyae, Selaginellaceae), a new species from East China and its phylogenetic position based on molecular data. PhytoKeys 202: 107-119. https://doi.org/10.3897/phytokeys.202.85410
|
A new spikemoss species, Selaginella wuyishanensis, is described and illustrated based on materials collected from Fujian Province, East China. The new species can be distinguished from S. lutchuensis Koidzumi and S. albociliata P. S. Wang by its leaves with extremely long cilia (up to 8 mm) and distinctly white margins, ovate ventral sporophylls, and sporophyll-pteryx completely inverted on dorsal sporophylls. In the present work, a molecular phylogeny, taxonomic description, distribution information, line drawing, and photographs of this new species are presented. A morphological comparison is also given to distinguish it from morphologically similar species in Selaginella sect. Tetragonostachyae (Hook. & Grev.) Hieron. & Sadeb.
Danxia landform, Selaginella albociliata, Selaginella subg. Heterostachys, species diversity
Selaginella P. Beauv. (Selaginellaceae) is the largest genus of seed-free vascular plants with more than 700 species worldwide (
Since 2019, we have conducted investigations into wild vascular plants in Wuyishan National Nature Reserve (WNNR) in Fujian Province, East China. Most of the Selaginella species we have encountered are common in WNNR and can be easily identified to described species. However, one species collected from Danxia regions of WNNR didn’t match species listed in available checklists and monographs or those recently described species from East Asia (
The gross morphology of the new species was observed and examined both from the fresh plants and dried herbarium specimens using SMZ1270 stereomicroscope (Nikon, Japan). For spore morphology, a scanning electron microscope (SEM) was used to observe the megaspores and microspores. Spore samples obtained from herbarium specimen were mounted on specimen tabs and then coated with platinum in a sputter coater. Observations were conducted using an ESEM-Quanta 200 (FEI, Hillsboro, Oregon, USA) with 15 Kv at Nanjing Forestry University, Nanjing, China. The quantitative characters of the new species were measured using the ImageJ software (
For the phylogenetic study, a total of 84 accessions representing 50 species of the genus were included, of which four accessions representing four species were selected as outgroups based on earlier phylogenetic analysis (
Based on our phylogenetic analysis, three collections from three different populations of the new species is in a polytomy with S. lutchensis and S. albociliata (Fig.
The maximum likelihood phylogeny of Selaginella wuyishanensis and its congeners based on plastid gene rbcL and nuclear locus ITS. Support values [maximum likelihood bootstrap support (MLBS) ≥ 50%, Bayesian inference posterior probability (BIPP) ≥ 0.5] are shown above the main branches. The dash (--) indicates MLBS < 50% or BIPP < 0.5.
Morphologically, Selaginella wuyishanensis is most similar to S. albociliata and S. lutchuensis in having plants creeping (Fig.
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.
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!).
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
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).
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.
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.
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).
The species epithet is based on the name of the famous mount Wuyishan, referring to the type locality of the new species.
1 | Leave margins denticulate and not white-margined | 2 |
– | Leave margins more or less ciliate and/or white-margined | 3 |
2 | Strobili non-resupinate | S. nipponica |
– | Strobili resupinate | S. heterostachys |
3 | Leaves not white-margined, both sides of ventral leaves long ciliolate at margins | 4 |
– | Leaves white-margined, acroscopic base of ventral leaves long ciliolate at margins, elsewhere denticulate or subentire | S. xipholepis |
4 | Ventral leave margins with short cilia up to 0.2 mm; dorsal leave margins loosely serrulate | S. lutchensis |
– | Ventral and dorsal leave margins with cilia up to 0.6 mm | 5 |
5 | Ventral sporophylls ovate-lanceolate with length-to-width ratio of ca. 3.2; megaspore surfaces with fine and low papillae structure | S. albociliata |
– | Ventral sporophylls ovate with length-to-width ratio of ca. 2.4; megaspore surfaces smooth | S. wuyishanensis |
This work was supported by the National Natural Science Foundation of China (#32100167) and the Project of Biological Resources Survey in Wuyishan National Park ([3500]HMGC[GK]2020006). We thank the editor and two anonymous reviewers for their helpful comments. Ke-Wang Xu, Shui-Fei Chen, and Xin-Mao Zhou: Conceptualization; Data curation; Formal analysis; Investigation; Methodology; Software; Validation; Writing – original draft. Ke-Wang Xu, Hong-Jin Wei, Qiang Song, Xiao Zheng, Meng Li, Yan-Ming Fang: Wild investigation (supporting), data curation (supporting), and original draft review and editing (supporting). Ke-Wang Xu, Hui Ding, Xin-Mao Zhou, and Yi-Fan Duan: Conceptualization (lead), Validation (lead), and review and editing (lead).
List of taxa sampled with information related to taxonomy, GenBank accession numbers (rbcL, 5.8S+ITS2), references, and voucher information. Herbarium acronyms follow Index Herbariorum (
Selaginella albociliata P.S.Wang (1) L.-B. Zhang et al. 5302 (CDBI), China (Guangxi), KT161379 (