Spiranthes

Taxobox
name = "Spiranthes"


image_width = 240px
image_caption = "Spiranthes cernua"
regnum = Plantae
divisio = Magnoliophyta
classis = Liliopsida
ordo = Asparagales
familia = Orchidaceae
subfamilia = Orchidoideae
tribus = Cranichideae
subtribus = Spiranthinae
genus = "Spiranthes"
genus_authority = Rich., 1817
type_species = "Ophrys spiralis" = "Spiranthes spiralis"
type_species_authority = (L.) Chevall. 1827
subdivision_ranks = Species
subdivision = See text.

"Spiranthes", commonly called Ladies'-tresses, is a genus of orchids (family (Orchidaceae) belonging to the subfamily Orchidoideae.

It has a very wide, almost continuous distribution, mostly in temperate zones of the northern hemisphere: Europe, North Africa, Asia, Australia, New Guinea, the Americas and the Caribbean. It is a provincially endangered orchid, in North America it can be found in Manitoba, Ontario and more than 20 American states. They grow in meadows, fields and savannas but are also found in forests, both on acid and calcareous soil. Most species tend to become weeds in disturbed areas, while they may be scarce in undisturbed areas.

Plants can grow to a height of 12 to 38 cm (4.5 to 15 inches). Spiranthes consists of perennial, terrestrial orchids with clustered, tuberous or rarely fibrous, fleshy roots. The leaves are basal or occasionally cauline (i.e. emerging from the stem). They are variable in shape. They range from broadly ovate to elliptic, or absent at flowering.

The flowering stem has foliaceous sheaths. The stem is erect and spiraling (as the name "Spiranthes" indicates). It carries persistent, sheathing bracts. The resupinate, tubular flowers are arranged in a more or less spirally twisted, showy or inconspicuous terminal spike. Their color is typically a shade of white or yellowish-white or even pink ( as in "Spiranthes sinensis").

This genus has undergone many taxonomic changes : originally "Spiranthes" contained all the species from the subtribe Spiranthinae. In 1920 Schlechter divided this genus in 24 genera. A revision by Williams in 1951 and by Schweinfurth in 1958, inflated the number of species of this genus again. Finally D. Szlachetko, with several studies in the 1990s, divided this genus in several genera, contained in 3 subtribes. During all these changes, there is only one species that has remained taxonomically unchanged : "Spiranthes parksii"

Flowers of this genus are commonly popular in Japan, where it is called "Nejibana" ("lit."twisting flower.)

Species

* "Spiranthes aestivalis" (Poir.) Rich. (1817) : Summer-flowering [Spiranthes (Western & Central Europe to NW. Africa)
* "Spiranthes angustilabris" J.J.Sm. (1913) (New Guinea)
* "Spiranthes brevilabris" Lindl. (1840) : Texas Ladies'-tresses (SE. U.S.A. to East Texas)
** "Spiranthes brevilabris" var. "brevilabris"
** "Spiranthes brevilabris" var. "floridana" (Wherry) Luer (1972).
* "Spiranthes casei" Catling & Cruise (1974 publ. 1975) : Case's ladies'-tresses (Eastern Canada to NE. U.S.A.)
** "Spiranthes casei" var. "casei"
** "Spiranthes casei" var. "novaescotiae" Catling (1981) (Nova Scotia)
* "Spiranthes cernua" (L.) Rich. (1817) : Nodding Ladies'-tresses (Eastern Canada to Central & Eastern U.S.A.)
* "Spiranthes delitescens" Sheviak (1990) : Reclusive Ladies'-tresses (Arizona)
* "Spiranthes diluvialis" Sheviak (1984) : Ute's Ladies'-tresses (NW. U.S.A. to Nebraska)
* "Spiranthes eatonii" Ames ex P.M.Br. (1999) : Eaton's Ladies'-tresses (SE. U.S.A. to E. Texas)
* "Spiranthes graminea" Lindl. in G.Bentham (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 (C. & E. Canada to C. & E. U.S.A)
** "Spiranthes lacera" var. "gracilis" : Slender Ladies'-tresses (Bigelow) Luer (1975) (S. Ontario to C. & E. U.S.A.)
** "Spiranthes lacera" var. "lacera"
* "Spiranthes laciniata" (Small) Ames (1905): Lace-lipped Ladies'-tresses (New Jersey to E. Texas)
* "Spiranthes longilabris" Lindl. (1840) : Giant-spiral Ladies'-tresses (SE. U.S.A. to E. Texas)
* "Spiranthes lucida" (H.H.Eaton) Ames (1908) : Shining Ladies'-tresses (SE. Canada, NC. & E. U.S.A.)
* "Spiranthes magnicamporum" Sheviak (1973) : Great Plains Ladies'-tresses (S. Canada to C. & EC. U.S.A.)
* "Spiranthes nebulorum" Catling & V.R.Catling (1988) (Mexico, Guatemala)
* "Spiranthes ochroleuca" (Rydb.) Rydb. (1932) : Yellow Nodding Ladies'-tresses (SE. Canada to E. U.S.A.)
* "Spiranthes odorata" (Nutt.) Lindl. (1840) : Fragrant Ladies'-tresses, Marsh Ladies'-tresses (SE. U.S.A. to SE. Oklahoma)
* "Spiranthes ovalis" Lindl. (1840) : October ladies'-tresses (Ontario to EC. & SE. U.S.A.)
** "Spiranthes ovalis" var. "erostellata" Catling (1983).
** "Spiranthes ovalis" var. "ovalis"
* "Spiranthes parksii" Correll (1947): Navasota Ladies'-tresses (Texas)
* "Spiranthes porrifolia" Lindl. (1840) : Leek-leaved Ladies'-tresses, Creamy ladies'-tresses (W. USA)
* "Spiranthes praecox" (Walter) S.Watson in A.Gray (1890) : Early-blooming [Spiranthes, Green-vein ladies'-tresses (New Jersey to E. Texas)
* "Spiranthes pusilla" (Blume) Miq. (1859) (Sumatra)
* "Spiranthes romanzoffiana" Cham. (1828) : Hooded Ladies'-tresses (Great Britain, Ireland, Subarctic America to N. & WC. U.S.A)
* "Spiranthes sinensis" (Pers.) Ames (1908) : Chinese [Spiranthes (E. European Russia to Pacific, Borneo, Java, Sumatra, Philippines, Australia, Tasmania, New Zealand, New Guinea, Samoa, Vanuatu)
** "Spiranthes sinensis" f. "autumnus" Tsukaya (2005) (Japan)
* "Spiranthes spiralis" (L.) Chevall. (1827) : Spiraled [Spiranthes (Europe, Mediterranean to W. Himalaya)
* "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 (E. & EC. U.S.A)
* "Spiranthes vernalis" Engelm. & A.Gray (1845): Spring Ladies'-tresses (Quebec, E. & EC. U.S.A, Mexico, Guatemala, Bahamas)

Natural hybrids

Since the species do not readily cross with each other, hybrids are rare in this genus.
* "Spiranthes" × "intermedia" Ames (1903) (SE. Canada to NE. U.S.A.)
* "Spiranthes" × "itchetuckneensis" P.M.Br. (1999) (Florida)
* "Spiranthes" × "simpsonii" Catling & Sheviak (1993) (SE. Canada to NC. U.S.A)

Dr. Charles Sheviak, a taxonomist with the New York State Museum, has suggested that "Spiranthes delitescens" is an amphiploid hybrid between two species with different chromosome numbers, possibly "Spiranthes vernalis" and "Spiranthes porrifolia" Sheviak (1990) (Arizona).

References

*cite journal| author = Schlechter, R. | title = Versuch einer systematischen Neuordnung der Spiranthinae | journal = Beih. Bot. Centralbl. | volume = 37 |pages=317–454| year = 1920 (in German)
*cite journal | author = Williams, L.O.| title = The Orchidaceae of Mexico| journal = Ceiba | volume = 2 |pages = 1–321| year = 1951
*cite journal | author = Schweinfurt C. | title = Orchids of Peru | journal = Fieldiana Bot. | volume = 30| pages = 1–260| year = 1958
*cite journal | author = Szlachetko D.L. | title = Studies on Spirantheae (Orchidaceae) I. Varia | journal = Fragm. Flor. Geobot.|volume = 41| pages = 845–863| year = 1996
*cite journal | author = Sheviak C. | title = A new Spiranthes (Orchidaceae) from the cienegas of southernmost Arizona | journal = Rhodora | volume = 92 | pages = 213–231 | year = 1990