''Pleurothallis'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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. Orchids are cosmopolitan plants that are found in almost every habitat on Eart ...

s commonly called bonnet orchids. The genus name is derived from the Greek word , meaning "riblike branches". This refers to the rib-like stems of many species. The genus is often abbreviated as "Pths" in horticultural trade. This was a huge genus, which contained more than 1,200

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

- the second largest in the

Orchidaceae Orchids are plants that belong to the family (biology), family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Orchids are cosmopolitan distribution, cosmopolitan plants that ...

after ''

Bulbophyllum ''Bulbophyllum'' is a genus of mostly Epiphyte, epiphytic and Lithophyte, lithophytic orchids in the Family (biology), family Orchidaceae. It is the largest genus in the orchid family and one of the List of the largest genera of flowering plants, ...

''. In 2004, it decreased by more than half when many species were moved into new genera.

Distribution

''Pleurothallis'' is a completely

New World The term "New World" is used to describe the majority of lands of Earth's Western Hemisphere, particularly the Americas, and sometimes Oceania."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: ...

group, widespread across much of

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

and the

West Indies The West Indies is an island subregion of the Americas, surrounded by the Atlantic Ocean, North Atlantic Ocean and the Caribbean Sea, which comprises 13 independent island country, island countries and 19 dependent territory, dependencies in thr ...

. Flora of North America lists one species in

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

''(P. gelida)'' but this has now been transferred to a different genus, ''

Stelis ''Stelis'', or leach orchids, are a large genus of orchids, with 1339 accepted species. The generic name ''Stelis'' is the Greek word for 'mistletoe', referring to the epiphytic habit of these species. These mainly epiphytic (rarely lithophyti ...

''. The center of diversity of the genus is in the high

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

, especially in the chain of cloud forests in

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

. ''Pleurothallis'' grows in dry or wet, tropical or temperate climates.

Description

As a group they show a huge range in vegetative form,

terrestrial Terrestrial refers to things related to land or the planet Earth, as opposed to extraterrestrial. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on o ...

epiphytic An epiphyte is a plant or plant-like organism that grows on the surface of another plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphyt ...

, and can be found as tall cane-like plants a meter or so high, clumped or trailing, pendent or climbing, erect or creeping, tufted and tiny, delicate moss-like species that can grow on the thinnest of twigs. But they have one common denominator: they all have two

pollinia A pollinium (: pollinia) is a coherent mass of pollen grains in a plant that are the product of only one anther, but are transferred, during pollination, as a single unit. This is regularly seen in plants such as orchids and many species of milkwee ...

. They have reduced their

pseudobulb In botany, a pseudobulb is a storage organ found in many epiphytic and terrestrial sympodial orchids. It is derived from a thickening of the part of a stem between leaf nodes and may be composed of just one internode or several, termed ''heter ...

s and instead, some species have thick succulent leaves. Their flowers are among the most diverse and unusual, although often very small, and specialize in using tiny

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

s such as

gnat GNAT is a free-software compiler for the Ada programming language which forms part of the GNU Compiler Collection (GCC). It supports all versions of the language, i.e. Ada 2012, Ada 2005, Ada 95 and Ada 83. Originally its ...

s, flies or small wasps for

pollination Pollination is the transfer of pollen from an anther of a plant to the stigma (botany), stigma of a plant, later enabling fertilisation and the production of seeds. Pollinating agents can be animals such as insects, for example bees, beetles or bu ...

Taxonomy

To bring some order in this extremely diverse genus, 29 subgenera and 25 sections had been created. Much of this work has been done by Dr. C. Luer of the

Missouri Botanical Garden The Missouri Botanical Garden is a botanical garden located at 4344 Shaw Boulevard in St. Louis, Missouri. It is also known informally as Shaw's Garden for founder and philanthropy, philanthropist Henry Shaw (philanthropist), Henry Shaw. I ...

. A new analysis, based on DNA testing, confirmed on the whole the classification of the subtribe Pleurothallidinae, with however ''Pleurothallis'' as the main difference. New genetic insight broke up this huge genus and made it more consistent with the principles of

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

genera and

evolution Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...

ary relationships. Several times before, a splitting up has been attempted, but there were always too many intermediate forms. In 2004 the genera ''

Acianthera ''Acianthera'' is a genus of orchids native to the tropical parts of the Western Hemisphere, especially Brazil.de Melo, M. C., Borba, E. L., & Paiva, E. A. S. (2010)Morphological and histological characterization of the osmophores and nectaries ...

'', '' Ancipitia'', '' Antilla'', '' Apoda-prorepentia'', '' Areldia'', '' Atopoglossum'', '' Brenesia'', '' Crocodeilanthe'' were created, incorporating a large number of former ''Pleurothallis'' species. The subgenera ''Pleurothallis'' and ''Specklinia'' are becoming separate genera, and the subgenus ''Acuminatae'' might become the proposed genus '' Anathallis''. Other allied genera include ''

Dracula ''Dracula'' is an 1897 Gothic fiction, Gothic horror fiction, horror novel by Irish author Bram Stoker. The narrative is Epistolary novel, related through letters, diary entries, and newspaper articles. It has no single protagonist and opens ...

'', ''

Masdevallia ''Masdevallia'', abbreviated Masd in horticultural trade, is a large genus of flowering plants of the Pleurothallidinae, a subtribe of the orchid family (Orchidaceae). There are over 500 species, grouped into several subgenera. The genus is na ...

'', '' Restrepia'', and ''

''.

Species

Kew Kew () is a district in the London Borough of Richmond upon Thames. Its population at the 2011 census was 11,436. Kew is the location of the Royal Botanic Gardens ("Kew Gardens"), now a World Heritage Site, which includes Kew Palace. Kew is ...

Plants of the World Online Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew. History Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ...

listed around 555 species in the genus. Selected species include:

References

* Luer, Carlyle; 1986 - Icones Pleurothallidinarum III: Systematics of ''Pleurothallis'' (Orchidaceae); Missouri Botanical Garden Press. * {{Authority control Pleurothallidinae genera