Spiranthes nivea var. papillata T.C. Hsu & Suetsugu, 2023

Suetsugu, Kenji & Hsu, Tian-Chuan, 2023, Taxonomic revision of the genus Spiranthes (Orchidaceae) in Taiwan, Phytotaxa 578 (1), pp. 1-10 : 6-7

Spiranthes nivea var. papillata T.C. Hsu & Suetsugu , var. nov. — Fig. 5 .

≡ Spiranthes minutiflora Hsu (2016: 187) in Hsu & Chung (2016), nom. illeg., non Richard & Galeotti (1845: 32).

Type:— TAIWAN. Ilan : Tsuifong Lake, 1800–1900 m elev., 3 June 2015, T.C. Hsu 7743 (holotype: TAIF496968 !) .

Diagnosis:— Spiranthes nivea var. papillata is morphologically distinguishable from S. nivea var. nivea by its more densely pubescent rachis and ovaries (vs. sparsely pubescent rachis and ovaries), narrower sepals that are white tinged with pink or purple at the apex (vs. wider and entirely white sepals), and papillose labellum disc (vs. almost glabrous labellum disc).

Morphological descriptions and illustrations: —See Hsu & Chung (2016: 187), as Spiranthes minutiflora .

Distribution and ecology: —This variety is currently recorded around Tsuifong Lake and Taipingshan in northeastern Taiwan. It grows on sunny grasslands, semi-open roadside slopes, and cliffs around 1800–2100 m elev. Flowers were observed from May to July.

Etymology:— The specific epithet is named after its papillate lip and papillate-pubescent rachis and ovaries that are diagnostic from the typical variety.

Additional specimens examined:— TAIWAN. Ilan Co.: Taipingshan, 21 May 2012, T.-C. Hsu 5742 (TAIF!); same loc., 23 June 2017, T.-C. Hsu 9299 (TAIF!); Tsuifeng Lake, 22 June 2017, T.-C. Hsu 9287 (TAIF!).

Taxonomic remarks: — Spiranthes nivea var. papillata shows morphological resemblance to S. nivea and S. hongkongensis , due to their shared autogamous reproductive biology. Althouth Lin (2019) considered it conspecific with S. hongkongensis , this taxon actually differs in having bracts that significantly exceed ovaries, smaller and glabrous basal labellum callosities, ovate labellum, and smaller column. These features imply a closer relationship to S. nivea , but it still differs from S. nivea var. nivea by several morphological characters mentioned in the diagnosis. Given that there are no significant differences in the labellum and column morphology, which are essential characteristics in species delimitation in S. sinensis species complex ( Pace et al. 2019), we concluded that the relatively minor differences are attributed to intraspecific variation, describing it as a new variety of S. nivea .

Figures

FIGURE 5. Spiranthes nivea var. papillata (Tian-Chuan Hsu 7743, TAIF). (A) Habit. (B) Flower, front view. (C) Flower, lateral view. (D) Dorsal sepal. (E) Petal. (F) Lateral sepal. (G) Labellum. (H) Labellum and column, lateral view. (I) Flattened labellum. (J) Close-up of basal callosities of labellum. (K) Ovary and column. (L) Column. Scale bars: 30 mm (A), 3 mm (B–I), 0.5 mm (J) and 1 mm (K–L).