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| Gastrochilus jiuzhaigouensis Jun Y.Zhang, D.L.Zhu & Y.Zhang, in Zhu, J.-Y. Zhang, Y. Zhang, Liao, He, Chen et Xu, 2025. |
Abstract
Gastrochilus jiuzhaigouensis (Orchidaceae), a new orchid species epiphytic on tree branches on the bank of an alpine lake at the famous Jiuzhaigou National Park in China, is described and illustrated. It differs from its morphologically similar species, G. bernhardtianus, by its shorter stems, obliquely linear-lanceolate leaves, reniform and revolute epichile without ornamentation, and the absence of a middle ridge at central callus of the epichile. To test its species status, sequences of the nuclear ribosomal internal transcribed spacer (nrITS) and four chloroplast DNA markers (matK, psbA-trnH, psbM-trnD, and trnL-F) were newly generated. Molecular phylogenetic analyses including 53 accessions of Gastrochilus species resolved it within the same clade as G. bernhardtianus, but with distinct boundary. Both morphological differences and phylogenetic evidence supported it a species new to science.
Key words: Gastrochilus, Jiuzhaigou, new species, Orchidaceae, phylogeny
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| Habitat and habit of Gastrochilus jiuzhaigouensis in situ. A, B. Habitat; C–E. Flowering plants of G. Jiuzhaigouensis growing on tree branches. [Images A–E. Photographed by Da-Lin Zhu]. |
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| Gastrochilus jiuzhaigouensis. A. Flowering plant; B. Leaves (B1: front view, B2: abaxial view); C. Flowers, front view; D. Flowers, abaxial view; E. Dissection of a flower (E1: dorsal sepal; E2-3: lateral sepals; E4-5: petals; E6: labellum); F. Anther cap; G. Pollinarium with pollinia; H. Raceme, lateral view; I. Labellum, lateral view. [Images A–I. photographed by Jun-Yi Zhang]. |
Gastrochilus jiuzhaigouensis Jun Y.Zhang, D.L.Zhu & Y.Zhang, sp. nov.
Diagnosis. It is most similar to G. bernhardtianus, but it can be distinguished by its shorter stem (0.5–1.2 vs. ca. 5.0 cm), obliquely linear-lanceolate leaves (vs. oblong-lanceolate leaves), reniform and revolute epichile (vs. transversely oblong and spread) without ornamentation (vs. two conic calli near its base), and absence of middle ridge (vs. distinctly ridged) at the middle of central callus on the epichile.
Da-Lin Zhu, Jun-Yi Zhang, Yue Zhang, Min Liao, Hai He, Ke Chen and Bo Xu. 2025. Gastrochilus jiuzhaigouensis (Orchidaceae, Epidendroideae), A New epiphytic orchid from Jiuzhaigou World Heritage Site, China. PhytoKeys. 265: 25-38. DOI: doi.org/10.3897/phytokeys.265.159138
