Description of Spiranthes
Found on 5 continents (Africa, Asia, Australia, Europe, and North America), Spiranthes is one of the most widely distributed genera of orchids on Earth. This genus has a long and confused taxonomic history; nearly every species in the subtribe Spiranthinae were at one time included under this genus. Today, approx. 34 species are recognized. Spiranthes is one of the few orchid genera to be most diverse in North America, with its center of diversity in the Southeastern United States.
Spiranthes are terrestrial deciduous herbs. Leaves are glabrous and are mainly arranged in a basal rosette. Flowers are resupinate and arranged in a loose to tight spiral on the inflorescence. Flowers are predominantly white with green or yellow lips, though one species is bright pink. The base of the lip has two prominent, sometimes curved, callosities. The lips of some species are prominently reflexed.
Molecular Biology and Genetics
Statistics of barcoding coverage
Specimens with Sequences:67
Specimens with Barcodes:50
Species With Barcodes:13
Spiranthes is a genus of orchids in the subfamily Orchidoideae. They are known commonly as ladies tresses, ladies'-tresses, or lady's tresses. The genus is distributed in the Americas, Eurasia, and Australia. The genus name Spiranthes is derived from the Greek speira ("coil") and anthos ("flower"), and was inspired by the spirally arranged inflorescence.
These are perennial herbs growing from fleshy root systems that are sometimes thick and appear tuberous. Most of the leaves are basal, but some species have leaves higher on the stem before the inflorescence matures, often taking the form of a sheath around the stem. The inflorescence is a terminal spike with flowers arranged in a loose or dense spiral. As in most other orchids, the flowers are resupinate, twisting during development into an upside-down position. The six tepals may be separate, or the three upper may be joined to form a hood over the lip petal. The lip is pouched and is thin to somewhat fleshy. The flowers are usually white, cream, or yellow, and at least one species has pink flowers.
- Spiranthes aestivalis (Poir.) Rich. (1817) – summer-flowering spiranthes (western & central Europe to northwestern Africa)
- Spiranthes angustilabris J.J.Sm. (1913) (New Guinea)
- Spiranthes brevilabris Lindl. (1840) – Texas ladies'-tresses (southeastern USA)
- Spiranthes casei Catling & Cruise (1974) – Case's ladies'-tresses (eastern Canada & USA)
- Spiranthes casei var. casei
- Spiranthes casei var. novaescotiae Catling (1981) (Nova Scotia)
- Spiranthes cernua (L.) Rich. (1817) – nodding ladies'-tresses (eastern Canada & USA)
- Spiranthes delitescens Sheviak (1990) – reclusive ladies'-tresses (Arizona)
- Spiranthes diluvialis Sheviak (1984) – Ute's ladies'-tresses (northwestern USA)
- Spiranthes eatonii Ames ex P.M.Br. (1999) – Eaton's ladies'-tresses (southeastern USA)
- Spiranthes graminea Lindl. (1840) – Canelo ladies'-tresses (Arizona, Mexico, Honduras, Nicaragua)
- Spiranthes hongkongensis S.Y.Hu & Barretto (1976) (Hong Kong)
- Spiranthes infernalis Sheviak (1989) – Ash Meadows ladies'-tresses (Nevada)
- Spiranthes lacera (Raf.) Raf. (1833) – northern slender ladies'-tresses (central and eastern Canada & USA)
- Spiranthes lacera var. gracilis
- Spiranthes lacera var. lacera
- Spiranthes laciniata (Small) Ames (1905) – lace-lipped ladies'-tresses (eastern USA)
- Spiranthes longilabris Lindl. (1840) – giant-spiral ladies'-tresses (southeastern USA)
- Spiranthes lucida (H.H.Eaton) Ames (1908) – shining ladies'-tresses (eastern Canada & USA)
- Spiranthes magnicamporum Sheviak (1973) – Great Plains ladies'-tresses (central and eastern Canada & USA)
- Spiranthes nebulorum Catling & V.R.Catling (1988) (Mexico, Guatemala)
- Spiranthes ochroleuca (Rydb.) Rydb. (1932) – yellow nodding ladies'-tresses (eastern Canada & USA)
- Spiranthes odorata (Nutt.) Lindl. (1840) – fragrant ladies'-tresses, marsh ladies'-tresses (southeastern USA)
- Spiranthes ovalis Lindl. (1840) – October ladies'-tresses (eastern Canada & USA)
- Spiranthes ovalis var. erostellata Catling (1983)
- Spiranthes ovalis var. ovalis Lindl.
- Spiranthes parksii Correll (1947) – Navasota ladies'-tresses (Texas)
- Spiranthes porrifolia Lindl. (1840) – leek-leaved ladies'-tresses, creamy ladies'-tresses (western USA)
- Spiranthes praecox (Walter) S.Watson in A.Gray (1890) – early-blooming spiranthes, green-vein ladies'-tresses (eastern USA)
- Spiranthes pusilla (Blume) Miq. (1859) (Sumatra)
- Spiranthes romanzoffiana Cham. (1828) – hooded ladies'-tresses (British Isles, North America)
- Spiranthes sinensis (Pers.) Ames (1908) – Chinese spiranthes (Eurasia, Pacific)
- Spiranthes sinensis f. autumnus Tsukaya (2005) (Japan)
- Spiranthes spiralis (L.) Chevall. (1827) – autumn ladies-tresses, spiraled spiranthes (Europe, Asia)
- Spiranthes sunii Boufford & Wen H. Zhang 2008 (Gansu)
- Spiranthes torta (Thunb.) Garay & H.R.Sweet in R.A.Howard (1974) – southern ladies'-tresses (Florida, Caribbean, Mexico, Central America)
- Spiranthes tuberosa Raf. (1833) – little ladies'-tresses (eastern USA)
- Spiranthes vernalis Engelm. & A.Gray (1845) – spring ladies'-tresses (North America, Guatemala)
- Spiranthes × intermedia Ames (1903) (eastern Canada & USA)
- Spiranthes × itchetuckneensis P.M.Br. (1999) (Florida)
- Spiranthes × simpsonii Catling & Sheviak (1993) (eastern Canada & USA)
This genus has undergone many taxonomic changes. Spiranthes once contained all the species from the subtribe Spiranthinae. In 1920, Spiranthes was split into 24 genera. Revisions in 1951 and 1958 placed more species into the genus. During the 1990s it was divided again.
It is difficult to clearly define the species of this taxon because some of them are polymorphic, taking a number of different forms. There is a species complex involving S. cernua, a "facultatively agamospermic polyploid compilospecies" which takes many forms that appear well-separated at times and have been mistaken for new species. An example might be S. parksii, a member of the complex and probably a descendent of S. cernua. It has been suggested that this species is just another rare form.
- Spiranthes. Integrated Taxonomic Information System (ITIS).
- Spiranthes. Flora of North America.
- Spiranthes. The Jepson eFlora 2013.
- Spiranthes. New South Wales Flora Online. National Herbarium, Royal Botanic Garden, Sydney.
- GRIN Species Records of Spiranthes.
- Spiranthes. USDA PLANTS.
- Sheviak, C. (1990). A new Spiranthes (Orchidaceae) from the cienegas of southernmost Arizona. Rhodora 92 213–31.
- Spiranthes. Flora of China.
- Schlechter, R. (1920). Versuch einer systematischen Neuordnung der Spiranthinae. Beih. Bot. Centralbl. 37 317–454. (in German)
- Williams, L. O. The Orchidaceae of Mexico - 4 Volumes. Ceiba Tegucigalpa. 1951.
- Schweinfurth, C. Orchids of Peru. Fieldiana Bot. 30 1–260. 1958.
- Szlachetko, D. L. (1996). Studies on Spirantheae Orchidaceae: I. Varia. Fragmenta Floristica et Geobotanica 41(2), 845-63.
- Dueck, L. A. and K. M. Cameron, K. M. (2007). Sequencing re-defines Spiranthes relationships, with implications for rare and endangered taxa. Lankesteriana 7(1-2), 190-95.
- Spiranthes cernua. Flora of North America.
- Spiranthes parksii. Flora of North America.
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