Monographs Details: Spiranthes Rich.
Authority: Ackerman, James D. 1995. An orchid flora of Puerto Rico and the Virgin Islands. Mem. New York Bot. Gard. 73: 1-203.
Description:Genus Description - Plants sympodial, caespitose terrestrials. Roots thick, fleshy, fasciculate. Leaves nonarticulate, several to numerous, basal, rarely cauline. Inflorescences terminal, erect, pedunculate, bracteate, racemes loosely or densely many-flowered and arranged in 1 or 2 spiraling rows. Flowers small, somewhat tubular, resupinate. Sepals free, similar, connivent with spreading apices; dorsal sepal concave to cucullate; lateral sepals oblique at base. Petals adnate to dorsal sepal. Lip mostly spatulate, concave to conduplicate, recurved, crisped or undulate, basally adnate to the sides of the column. Column short, terete; foot short; stigmas confluent, entire, rostellum and viscidium elongate; anther stalked, dorsal; pollinia 2, clavate, mealy. Fruit a capsule.
Discussion:Spiranthes Richard, De Orchid. Eur. 20. 1817. Type species. Spiranthes spiralis (Linnaeus) K. Koch based on Ophyrs spiralis L. of Europe.
A cosmopolitan genus, principally of north temperate and subtropical regions, consisting of about 45 species. The generic name refers to the spiral arrangement of the flowers on the inflorescence axis.
Taxonomic Notes. Recent treatments of the subtribe Spiranthinae limit the circumscription of Spiranthes and segregate the majority of tropical species into other genera (Garay, 1980b; Balogh, 1982; Burns-Balogh & Robinson, 1983), but there is little agreement on how many segregate genera should be recognized. Eight species of Spiranthes have been listed for Puerto Rico, but I now place seven of them in other genera (Cyclopogon, Hapalorchis, Mesadenus, Pelexia, and Stenorrhynchos).
Special Literature. Garay, 1980b; Balogh, 1982; Greenwood, 1982; Dressier, 1993.