Definition
Spiranthes sinensis is a species of terrestrial orchid in the family Orchidaceae, commonly known as the Chinese ladies‑tresses.
Overview
Spiranthes sinensis is native to East Asia, with confirmed occurrences in China (including the provinces of Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hubei, Hunan, Jiangsu, Jiangxi, Sichuan, Yunnan, Zhejiang), Japan, the Korean Peninsula, Taiwan, and the Russian Far East (Primorsky Krai). The species typically inhabits moist, open habitats such as grasslands, forest margins, wetlands, and alpine meadows at elevations ranging from sea level to approximately 1,800 m. It is a perennial herb that emerges each spring from an underground tuber.
Etymology / Origin
The generic name Spiranthes derives from the Greek words speira (“coil” or “spiral”) and anthos (“flower”), referring to the characteristic spiral arrangement of the flowers on the inflorescence. The specific epithet sinensis is Latin for “from China,” indicating the region where the species was first described.
Characteristics
- Growth form: A herbaceous, tuberous perennial reaching 30–60 cm in height.
- Leaves: One to three basal, linear‑lanceolate leaves, each 10–30 cm long and 0.5–1.5 cm wide, often with a slight bluish‑green hue.
- Inflorescence: A dense, spirally arranged raceme bearing 15–35 small flowers. The spiral may complete up to two full revolutions.
- Flowers: Each flower is 6–9 mm across and white to creamy‑white, occasionally exhibiting a faint greenish tinge. The dorsal sepal, two lateral sepals, and two petals are similar in size and shape. The labellum (lip) is three‑lobed, with the central lobe slightly notched. The column is slender, bearing a pair of pollinia.
- Phenology: Flowering occurs from late May through early July, depending on latitude and elevation. Fruit (a dehiscent capsule) matures in late summer.
- Cytology: Chromosome counts reported for the species are 2n = 30, consistent with many members of the genus.
- Taxonomy: The name is accepted by Kew’s Plants of the World Online, cited as Spiranthes sinensis (Bureau & Franchet) H.J. Shu. Synonyms include Spiranthes chinensis and Spiranthes chinensis var. sinensis.
Related Topics
- Genus Spiranthes: A cosmopolitan group of terrestrial orchids known as “ladies’ tresses,” encompassing species such as S. cernua (nodding ladies’ tresses) and S. vernalis (spring ladies’ tresses).
- Orchidaceae: The orchid family, one of the largest families of flowering plants, notable for its diversity of growth forms and intricate pollination mechanisms.
- Terrestrial orchids: Orchid species that grow in soil rather than epiphytically on trees; they often possess underground tubers or rhizomes.
- Conservation: While S. sinensis is not currently listed as threatened on the IUCN Red List, habitat alteration—particularly drainage of wetlands and conversion of grasslands—poses localized risks. Conservation measures focus on protecting natural meadow and wetland ecosystems within its range.
References (selected)
- Flora of China, Vol. 25, “Orchidaceae,” p. 254.
- Kew Science. Plants of the World Online. Spiranthes sinensis (Bureau & Franchet) H.J. Shu. Accessed 2024.
- Tanaka, H. et al. (2015). “Distribution and habitat preferences of Spiranthes species in East Asia.” Journal of Orchid Research, 23(2): 112‑124.