(Pers.) Ames
Description
Spiranthes sinensis, the Chinese ladies'-tresses, is one of the most widespread terrestrial orchids of the Old World, documented in GBIF by some 7880 occurrences spanning eastern Asia from China, Japan, Korea and Russia through India, Nepal, Bhutan and Southeast Asia to Australia, New Caledonia and Sri Lanka. It occupies open, moist grassland, marshy meadows, streambanks, paddy margins and grassy slopes from near sea level to about 3000 m. The photographed Himalayan plants from Trashigang in Bhutan at 1450 m in May, the Tsang-Chu at 1800 m in April and Amjilassa in eastern Nepal at 2300 m in March illustrate its tolerance of a wide elevational and seasonal range in damp, sunny situations.
It is a slender terrestrial orchid with fleshy, fasciculate, tuberous roots and a tuft of linear to oblanceolate basal leaves. The erect, finely pubescent inflorescence bears numerous small flowers arranged in a characteristic single spiral around the axis. The flowers are typically pink to rose-purple with a white, recurved, crisped-margined labellum bearing a yellowish, papillose central callus; the dorsal sepal and petals converge to form a hood over the short column. The fruit is a small, erect, ellipsoid capsule releasing dust-like seeds.
A member of subtribe Spiranthinae of the Orchidaceae (here under the input spelling Orchideaceae), S. sinensis forms a taxonomically complex, polyploid-rich aggregate from which several segregates such as S. australis and S. hongkongensis have been recognised. Like most orchids it depends on mycorrhizal fungi for germination and is pollinated chiefly by bees. Despite local declines from wetland drainage, its enormous range and weedy persistence in disturbed grassland make it of Least Concern, though it is protected under CITES Appendix II as for all orchids.
Author: (Pers.) Ames · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Annotated Checklist of the Flowering Plants of Nepal, Pridgeon et al. Genera Orchidacearum