Tuesday, August 8, 2023

[Botany • 2023] Thrixspermum taeniophyllum (Orchidaceae: Epidendroideae) • A New Species from southwest China, based on Molecular and Morphological Evidence


 Thrixspermum taeniophyllum Jun Y.Zhang, H.He & Yue H.Cheng, 

Zhang, Cheng, Liao, Liu, Yang, Xu et He, 2023.
带叶白点兰  ||  DOI: 10.3897/phytokeys.230.104273

Abstract
Thrixspermum taeniophyllum is described as a new orchid species from Wenchuan County, Sichuan Province of southwest China. It is morphologically similar to T. japonicum, but it differs from the latter in having branched stems, slightly fleshy strap-shaped leaves, longer inflorescences with 3–6 flowers and a capitate gynandrium with a lip-shaped mouth opening. Its species status is also supported by molecular phylogenetic analyses, based on nuclear ribosome internal transcribed spacer (nrITS) and three chloroplast DNA fragments (matK, psbA-trnH and trnL-F), which showed distinct systematic boundaries from the most morphologically similar T. japonicum and their morphological relatives T. saruwatarii and T. pygmaeum.

Key words: Epiphytic orchid, flora of Sichuan, phylogeny, systematic position, taxonomy

 Thrixspermum taeniophyllum 
A flowering plant B leaves C inflorescence D part of the rachis showing persistent bracts E flower in front view F dissection of a flower (F1: dorsal sepal; F2–F3: petals; F4–F5: sepals; F6: labellum) G, H labellum I pollinia J gynandrium and ovary.

 Thrixspermum taeniophyllum Jun Y.Zhang, H.He & Yue H.Cheng, sp. nov.

Diagnosis: It is most similar to Thrixspermum japonicum in morphology, but it differs from the latter by its often-branched stems (vs. unbranched stems), slightly fleshy strap-shaped leaves 5–7 cm long (vs. thinly leathery oblong leaves 2–4 cm long), longer inflorescences with 3–6 flowers (vs. shorter inflorescences with 2–3 flowers) and its capitate gynandrium with a lip-shaped mouth opening (vs. conical gynandrium with a triangular mouth opening). It also resembles T. saruwatarii and T. pygmaeum and morphological comparison amongst the four species is visualised in Fig. 1 and summarised in Table 1.

Etymology: The specific epithet taeniophyllum is a compound adjective referring to the shape of leaves of this new species. 
A Chinese name, dai ye bai dian lan (带叶白点兰), is also suggested, based on the its leaf feature.


 Jun-Yi Zhang, Yue-Hong Cheng, Min Liao, Gui-Ying Liu, Pan-Yan Yang, Bo Xu and Hai He. 2023. Thrixspermum taeniophyllum (Orchidaceae, Epidendroideae), A New Species from southwest China, based on Molecular and Morphological Evidence. PhytoKeys. 230: 145-156.  DOI: 10.3897/phytokeys.230.104273