Spiranthes

Spiranthes
Spiranthes spiralis
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Monocots
Order:	Asparagales
Family:	Orchidaceae
Subfamily:	Orchidoideae
Tribe:	Cranichideae
Subtribe:	Spiranthinae
Genus:	Spiranthes Rich., 1817
Type species
Ophrys spiralis = Spiranthes spiralis (L.) Chevall. 1827
Species
See text.

See text.

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, yellow, scarlet or red, and at least one species has pink flowers.

There are about 42 to 45 species in the genus.

Species include:

Hybrids include:

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.

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Wikipedia