The

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

''Platanthera'' belongs to the subfamily Orchidoideae of the family

Orchidaceae Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowerin ...

, and comprises about 150

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of floweri ...

s. The members of this genus, known as the butterfly orchids or fringed orchids, were previously included in the genus '' Orchis'', which is a close relative (along with the genus ''

Habenaria ''Habenaria'', commonly called rein orchids or bog orchids, is a widely distributed genus of orchids in the tribe Orchideae. About 880 species of ''Habenaria'' have been formally described. They are native to every continent except Antarctica, g ...

''). They are distributed throughout the temperate regions of the

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...

. They are terrestrial and have tubercules.

Etymology

Louis Claude Richard chose the name ''Platanthera'' for this genus; it comes from the Greek and means "broad or wide

anther The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

," referring to the separation of the base of the pollinia in the type species of the genus. Richard felt that this characteristic distinguished the genus ''Platanthera'' from both the genus '' Orchis'' and the genus ''

''. However, today the defining characteristics of the genus are generally accepted to be the absence of both stigmatic processes (typical in ''Habenaria'') and ovoid root-tuberoids (characteristic of both ''Habenaria'' and ''Orchis''). Still, '' P. nivea'', '' P. clavellata'' and '' P. integra'' all have stigmatic processes, showing the limitations of morphological characteristics in defining this clade.

Description and habitat

Species of ''Platanthera'' are perennial terrestrial herbs, erect in habit. The roots are fasciculate and typically fleshy and slender, although they may be somewhat tuberous; if tuberous they are lanceolate to fusiform and not ovoid. The leaves are generally fleshy and range from oblong or ovoid to lanceolate. Leaf shape often varies with the lower leaves more ovoid in shape, progressively becoming more lanceolate as they progress up the scape; floral bracts, if present, are lanceolate to linear. The base of the leaves typically sheathes the stem. The inflorescence is terminal and solitary, and the flowers form a cylindrical spike that ranges from sparse to dense. The flowers are typically

resupinate Resupination is derived from the Latin word ''resupinus'', meaning "bent back with the face upward" or "on the back". " Resupination" is the noun form of the adjective "resupine" which means "being upside-down, supine or facing upward". The wor ...

, and often showy and colorful. Petal colors range from purple, orange and yellow to green and white. The petals and labellum are typically entire, but in a number of North American species they may be fringed or edentate; in this group of species the labellum is also often deeply lobed or auricuate. The seed capsules are cylindrical and ridged. These terrestrial orchids develop in a wide range of soil types and habitats, from strongly basic soils to deeply acidic bog soils, from

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

openings and in clearings within the forest to open tundra and various wetland habitats. Some ''Platanthera'' species are pollinated by mosquitoes.

Species

Many species can cross-fertilise, resulting in great morphological variety and complicating classification. The type species is '' Platanthera bifolia''. More than 400 species, subspecies, and varieties have been described, and a 1997 study estimated around 85 species were clearly defined, though these quantities vary considerably between evolving classification systems, and naturally change as specimens are reanalyzed or newly acquired. "Species of ''Platanthera'' occur in North America, Asia, Europe, North Africa, Borneo, and Sarawak. Major centers of diversity are found in North America and East Asia." The Plant List which tracks botanical names lists 152 accepted species names in the genus ''Platanthera'' as of 2022, along with 100ds of infraspecific names. They include: Species endemic to North America Other species native to North America Other species native to Asia Other species

References

External links

* *
''Platanthera'' Interactive Key at Utah State University
* ttp://www.orchidsrepbiol.de/cgi-bin/img_db/img_displayTaxon.pl?db=Platanthera Platanthera picture database {{Taxonbar, from=Q161849 Orchideae genera

Etymology

Description and habitat

Species

Further reading

References

External links