Spiranthes
Encyclopedia
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 root
s. 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 bract
s. The resupinate, tubular flower
s 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 (lit.twisting flower.)
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).
However, more complicated forms of gene flow are present in this genus. There are a number of polyploid species known as the S. cernua complex, which are characterized by apomixis
and polyembryony
. This complex includes S. cernua, S. parksii, and perhaps S. casei. Related species, which include at least some plants identified as S. magnicamporum, S. ochroleuca, and S. odorata, are diploids and there is gene flow
from the diploids to the polyploids, but not in reverse.
Orchidaceae
The Orchidaceae, commonly referred to as the orchid family, is a morphologically diverse and widespread family of monocots in the order Asparagales. Along with the Asteraceae, it is one of the two largest families of flowering plants, with between 21,950 and 26,049 currently accepted species,...
) belonging to the subfamily Orchidoideae
Orchidoideae
The Orchidoideae, or the orchidoid orchids, are a subfamily of the orchid family .They typically contain the orchids with a single , fertile anther which is erect and basitonic....
.
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 root
Root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...
s. 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
Plant stem
A stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaves, inflorescence , conifer cones, roots, other stems etc. The internodes distance one node from another...
has foliaceous sheaths. The stem is erect and spiraling (as the name Spiranthes indicates). It carries persistent, sheathing bract
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
s. The resupinate, tubular flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s 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
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, where it is called (lit.twisting flower.)
Species
- Spiranthes aestivalisSpiranthes aestivalisSpiranthes aestivalis, commonly called the Summer Lady's-tresses, is a species of orchid....
(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 cernuaSpiranthes cernuaSpiranthes cernua, commonly called the Nodding Ladies'-tresses, is a species of orchid occurring from eastern Canada to the central and eastern United States....
(L.) Rich. (1817) : Nodding Ladies'-tresses (Eastern Canada to Central & Eastern U.S.A.) - Spiranthes delitescensSpiranthes delitescensSpiranthes delitescens is a rare species of orchid known by the common name Canelo Hills lady's tresses, reclusive lady's tresses, and Madrean lady's tresses. It is native to Arizona in the United States, where there are only four occurrences. It is threatened by the loss and degradation of its...
Sheviak (1990) : Reclusive Ladies'-tresses (Arizona) - Spiranthes diluvialisSpiranthes diluvialisSpiranthes diluvialis is a rare species of orchid known by several common names, including Ute lady's tresses . The species name diluvialis means "of the flood"...
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 ochroleucaSpiranthes ochroleucaSpiranthes ochroleuca, commonly called the Yellow Nodding Ladies'-tresses, is a species of orchid occurring from southeastern Canada to the eastern United States....
(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 parksiiSpiranthes parksiiSpiranthes parksii is an endangered species of orchid endemic to Texas, United States. The flower was first discovered in 1945 and was first described by Donovan Stewart Correll in his 1950 book, Native Orchids of North America North of Mexico...
Correll (1947): Navasota Ladies'-tresses (Texas) - Spiranthes porrifoliaSpiranthes porrifoliaSpiranthes porrifolia is a species of orchid known by the common name creamy lady's tresses. It is native to the western United States from Washington and Idaho to southern California. It can be found in moist and wet habitat, such as mountain meadows, freshwater swamps, and riverbanks...
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 romanzoffianaSpiranthes romanzoffianaSpiranthes romanzoffiana, commonly known as the Hooded Lady's-tresses, is a species of orchid. Collected by Chamisso during the Romanzov expedition it was described by him in 1828 and named for Count Nikolay Rumyantsev who financed it....
Cham. (1828) : Hooded Ladies'-tresses (Great Britain, Ireland, Subarctic America to N. & WC. U.S.A) - Spiranthes sinensisSpiranthes sinensisSpiranthes sinensis, commonly known as the Chinese Spiranthes, is a species of orchid occurring in much of eastern Asia, west to the Himalayas, south and east to New Zealand, and north to Siberia....
(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) : Autumn Ladies-tresses, 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)
Division into species and 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).
Apomixis
In botany, apomixis was defined by Winkler as replacement of the normal sexual reproduction by asexual reproduction, without fertilization. This definition notably does not mention meiosis...
and polyembryony
Polyembryony
Polyembryony is the phenomenon of two or more embryos developing from a single fertilized egg . Polyembryony occurs regularly in many plants and animals. The nine banded armadillo, for instance, usually gives birth to four identical young...
. This complex includes S. cernua, S. parksii, and perhaps S. casei. Related species, which include at least some plants identified as S. magnicamporum, S. ochroleuca, and S. odorata, are diploids and there is gene flow
Gene flow
In population genetics, gene flow is the transfer of alleles of genes from one population to another.Migration into or out of a population may be responsible for a marked change in allele frequencies...
from the diploids to the polyploids, but not in reverse.