Spiranthes sinensis ( Persoon 1807: 511 ) Ames (1908: 53)

Suetsugu, Kenji & Hsu, Tian-Chuan, 2023, Taxonomic revision of the genus Spiranthes (Orchidaceae) in Taiwan, Phytotaxa 578 (1), pp. 1-10 : 3-5

Spiranthes sinensis ( Persoon 1807: 511) Ames (1908: 53) — Fig. 1 .

Type:— CHINA: prope Cantonem Sinarum, 1790, J. de Loureiro 5221 (holotype: P00150857, image!) .

= Spiranthes suishaensis ( Hayata 1916: 86) Schlechter (1919: 161) ≡ Spiranthes australis (R. Brown 1810: 319) Lindley (1824: 823) var. suishaensis Hayata (1916: 86) . Type:— TAIWAN. Nantou: Lake Suisha, 28 April 1916, B. Hayata s.n. (holotype: TI00010424!).— Fig. 2 .

= Spiranthes pitouchaoensis S.S. Ying (2022: 19) , syn. nov. Type:— TAIWAN. New Taipei: Ruifang District, Pitouchao, 28 June 2020, S.S.Ying s.n. (holotype: NTUF, not located; image available in Ying (2022: 23)).

Morphological descriptions and illustrations: —See Lin (1975: 244–245; 2019: 267; f. 118; pl. 13), Liu & Su (1978: 1103; pl. 1642), Surveswaran et al. (2017: 125; f. 4) and Hsu & Chung (2016: 188).

Distribution and Ecology: — Spiranthes sinensis occurs from the southern part of the Hengduan Mountains, eastward across northern Laos, northern Vietnam, southern and eastern China, northward across Taiwan and the Ryukyu Islands, southward across the northern Malay Archipelago, New Guinea, and New Caledonia. In Taiwan, this species is widespread throughout the main island and recorded from neighboring islets, including Pengchiayu, Lyudao (Green Island) and Lanyu (Orchid Island). It usually occurs at sunny grassy places in lowland regions from sea level to ca. 1000 m elev. and occasionally grows on roadside slopes in mountainous regions between 1000–2000 m elev. Flowers were mainly observed from March to May in lowland populations and from May to September in mountainous populations.

Additional specimens examined: — TAIWAN. “ Formosa ”: 1862, R. Swinhoe s.n. (K!) ; April 1874, W. Campbell s.n. (BM!) ; 11 March 1912, W.R. Price 190A (K!) . Keelung City: Pengchiayu , 7 June 2005, S.- W. Chung 7742 (TAIF!) . New Taipei City: Tamsuy , 1864, R. Oldham 183 (BM!, K!) ; Urai, April 1914, U. Faurie 926 (BM!) ; Shihding Service Area, 18 March 2013, T.- C. Hsu 6393 (TAIF!) . Taichung City: Gaomei , 27 April 2017, T.- C. Hsu 9045 (TAIF!) ; Nantou Co.: Suisha , s.a., B. Hayata s.n. (TAIF!) ; Sun Moon Lake, 28 April 2008, T.- C. Hsu 1347 (TAIF!) . Hualien Co.: Hoping Logging Trail, 25 September 2007, T.- T. Ho 215 (TAIF!) ; Changhong Bridge, 5 April 2018, T.- C. Hsu 10400 (TAIF!) . Taitung Co.: Lichia Logging Trail, 4 April 2018, T.- C. Hsu 10399 (TAIF!) ; Lyudao Island, Chaojih Hot Spring , 17 April 2018, T.- C. Hsu 10475 (TAIF!) ; Lanyu Island, Yehyin , 27 March 2018, T.- C. Hsu 10318 (TAIF!) . JAPAN. Kyushu Dist., Kagoshima Pref .: Amami Island , 8 May 2016, M. Takashi HH111 (SPMN!) . Okinawa Pref.: Okinawa Island , 17 April 2017, A. Naiki 9922 (RYU!) ; Iriomote Island, 18 April 2017, A. Naiki 9925 (RYU!) ; Ishigaki Island, 27 March 2017, A. Soejima HH672 (SPMN!) .

Taxonomic remarks: — Spiranthes sinensis displays allogamous features, including a well-developed rostellum that separates the stigma and pollinarium of each flower, pollinia with a viscidium, and suborbicular stigma, whereas S. hongkongensis and S. nivea has a degenerated rostellum, pollinia without a viscidium, and a distinctly 3-lobed stigma. Because species in the S. sinensis species complex often have pink flowers, the members with entirely white flowers were traditionally recognized as a distinct species only due to their white flowers ( Pace et al. 2019). However, as demonstrated by Pace et al. (2019), it is not appropriate to delimitate Spiranthes species based solely on flower color. Because we could not recognize any distinct morphological differences between S. sinensis and S. suishaensis other than floral coloration ( Figs. 1–2 ), we concluded S. suishaensis is a synonym of S. sinensis . For a list of synonyms of S. sinensis other than S. suishaensis and S. pitouchaoensis , see Pace et al. (2019).

Figures

FIGURE 1. Spiranthes sinensis (Tian-Chuan Hsu 10400 [A] & Tian-Chuan Hsu 6393 [B–L], 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).

FIGURE 2. Spiranthes suishaensis (holotype). (A) Habit. (B) Close-up view of inflorescence. (C) Flower, lateral view. (D) Dorsal sepal. (E) Petal. (F) Lateral sepal. (G) Labellum and column. Rostellum is indicated by the arrow. (H) Close-up of papillate labellum disc. (I) Column, upper view. (J) Column, bottom view. (K) Pollinarium. Scale bars: 100 mm (A), 3 mm (B–G) and 1 mm (H–K).