''Oncidium'', abbreviated as Onc. in the horticultural trade, 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 ...

that, , contains about 340

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), ...

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 from the subtribe Oncidiinae of the orchid family Orchidaceae. It is distributed across tropical and subtropical America from

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 ...

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 ...

to northern

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

, with one species (''O. ensatum'') extending into Florida. Common names for plants in this genus include dancing-lady orchid and golden shower orchid. A 2008

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

study labeled the ''Oncidium'' alliance "grossly

polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...

." In the same year, the American Orchid Society labeled the genus a "dumping ground".Lindleyana : The scientific journal of the American Orchid Society. December 2008 Pg 20 A consensus announced in April 2013 resulted in major taxonomic changes to ''Oncidium'', '' Gomesa'', '' Odontoglossum'', ''

Miltonia ''Miltonia'', abbreviated Milt. in the horticultural trade, is an orchid genus comprising twelve epiphyte species and eight natural hybrids. The miltonias are exclusively inhabitants of Brazil, except for one species whose range extends from Braz ...

'', and others. Much of this debate and subsequent housekeeping was initiated by significant research for the scientific publication ''Genera Orchidacearum'' Volume 5. As a result, much of the information in this article is now

deprecated Deprecation is the discouragement of use of something human-made, such as a term, feature, design, or practice. Typically something is deprecated because it is claimed to be inferior compared to other options available. Something may be deprec ...

, but still of great value. One significant change is the move of most Brazilian ''Oncidium'' with a fused lateral sepal to the genus '' Gomesa''. The Royal Horticultural Society system, the World Checklist of Monocots database and the American Orchid Society have updated their databases to reflect most of these changes.

Description

This genus was first described by

Olof Swartz Olof Peter Swartz (21 September 1760 – 19 September 1818) was a Swedish botanist and taxonomist. He is best known for his taxonomic work and studies into pteridophytes, but also studied orchids, mosses and lichens. Biography Olof Swartz a ...

in 1800 with the orchid ''Oncidium altissimum'', which has become the type species. Its name is derived from the Greek word ὀγκος, ''onkos'', meaning "swelling". This refers to the callus at the lower lip. Most species in the genus are

epiphytes 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 ...

(growing on other plants), although some are

lithophyte Lithophytes are plants that grow in or on rocks. They can be classified as either epilithic (or epipetric) or endolithic; epilithic lithophytes grow on the surfaces of rocks, while endolithic lithophytes grow in the crevices of rocks (and are als ...

s (growing on rocks) or terrestrials (growing in soil). They are widespread from northern

, the

Caribbean The Caribbean ( , ; ; ; ) is a region in the middle of the Americas centered around the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean, mostly overlapping with the West Indies. Bordered by North America to the north, Central America ...

, and some parts of South

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 ...

to South America. They usually occur in seasonally dry areas. They can be divided into three categories, according to their growth pattern: * Some have green

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 long

raceme A raceme () or racemoid is an unbranched, indeterminate growth, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are ...

s with small flowers and a dominant

lip The lips are a horizontal pair of soft appendages attached to the jaws and are the most visible part of the mouth of many animals, including humans. Mammal lips are soft, movable and serve to facilitate the ingestion of food (e.g. sucklin ...

. They are mostly golden yellow with or without reddish-brown barring, but some are brown or yellowish-brown. Other ''Oncidium'' species have white and pink blooms, while some even have startling, deep red colors in their flowers. * Another group has extremely small pseudobulbs and stiff, erect, solitary

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

. These cylindrical leaves act as a water reserve. They have long racemes with yellow flowers that seem to fan out at the top. Sizes of these orchids can vary from miniature plants of a couple of centimetres to giants with 30 cm-long leaves and racemes of more than one metre long. These species, known as the Mule-Ears, are now classed as '' Psychopsis''. * Formerly there was a third group, called the Variegata or equitant oncidiums. They have no pseudobulbs, giving fan-shaped shoots of less than 15 cm, with triangular section leaves. These oval, broad and spongy leaves act as storage organs. Their flowers are most complicated with exquisite colors. The sepals are somewhat fleshy. The petals and the lip are membranaceous. These orchids are now classified as '' Tolumnia''. ''Cyrtochilum'' is another

that many ''Oncidium'' species have been reclassified into; ''Cyrtochilum'' species have extremely long, winding inflorescences that can sometimes reach 20' or more, curled petals that result in three-pointed blooms, and rambling growth habits in which each new pseudobulb appears on top of the old one. ''Oncidium'' species are characterised by the following properties : * presence of

column A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member ...

wings, * presence of a complicated callus on the

(this can be used to separate the taxa), *

s with one to three leaves, * several basal

bract In botany, a bract is a modified or specialized leaf, associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves in size, color, shape or texture. They also lo ...

s at the base of the pseudobulbs. The

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s come in shades of yellow, red, white and pink. The petals are often ruffled on the edges, as is the

. The lip is enormous, partially blocking the small petals and sepals. Some ''Oncidium'' orchids are very tall: ''

Oncidium altissimum ''Oncidium altissimum'', Wydler's dancing-lady orchid, is a species of orchid native to the West Indies (Cuba, Puerto Rico and the Lesser Antilles), with an 18th-Century citation from Jamaica. This name should not be confused with the illegitim ...

'' and '' Oncidium baueri'' can grow to a height of 5 m. They are known as 'spray orchids' among some florists. They are very varied and are easily hybridised with other closely related genera forming the ''Oncidium'' alliance (''Miltonia'', '' Cuitlauzina'', '' Miltoniopsis'', '' Leochilus'', '' Comparettia'', '' Cyrtochilum'', '' Tolumnia'', '' Rhynchostele'' ormerly ''Lemboglossum'' ''Psychopsis'', etc.). Some of the best ''Oncidium'' alliance hybrids originate from '' Oncidium tigrinum'' and '' Oncidium incurvum'' when crossed with species formerly placed in ''Odontoglossum'', although hybridization possibilities of this group of orchids are endless, and there are literally hundreds of thousands of hybrids in the ''Oncidium'' alliance.

Selected species

Selected species accepted by Plants of the World Online : *''

'' : " Wydler's dancing-lady orchid" (Jamaica) *'' Oncidium baueri'' (Trop. America) *'' Oncidium cheirophorum'' (Mexico - Chiapas to Colombia) *'' Oncidium citrinum'' (Trinidad to Venezuela) *'' Oncidium deltoideum'' (N. Peru) *'' Oncidium dichromaticum'' (Costa Rica to Colombia) *'' Oncidium ensatum'' : (S. Mexico, Belize, Cuba, Florida, Bahamas, NW. Venezuela) *'' Oncidium fuscatum'' (Ecuador to Peru) *'' Oncidium geertianum'' (C. & SW. Mexico) *'' Oncidium graminifolium'' (Mexico to C. America) *'' Oncidium harryanum'' (Colombia) *'' Oncidium hastatum'' (Mexico) *'' Oncidium hastilabium'' (W. South America) *'' Oncidium incurvum'' (Mexico - Veracruz to Chiapas) *'' Oncidium lentiginosum'' (Colombia to N. Venezuela) *'' Oncidium leucochilum'' (SE. Mexico to Guatemala) *'' Oncidium lineoligerum'' (N. Peru) *'' Oncidium maculatum'' (Mexico to C. America) *'' Oncidium naevium'' (Colombia to Guyana) *'' Oncidium noezlianum'' (N. Peru to Bolivia) *'' Oncidium ornithorhynchum'' (Mexico to C. America) *'' Oncidium reflexum'' (SW. Mexico) *'' Oncidium sphacelatum'' (Mexico to C. America, SE. Venezuela) *'' Oncidium strictum'' (Cogn.) M.W.Chase & N.H.Williams (Ecuador, Peru) *'' Oncidium wentworthianum'' (Mexico – Chiapas to El Salvador)

Former species

Selected species not accepted by Plants of the World Online : *'' Oncidium amictum'' → ''Gomesa'' × ''amicta'' (SE. Brazil) *'' Oncidium auricula'' → '' Grandiphyllum auricula'' (SE. Brazil) *'' Oncidium auriferum'' → '' Vitekorchis aurifera'' (Colombia to NW. Venezuela) *'' Oncidium bicolor'' → '' Gomesa bicolor'' (NE. Venezuela to Brazil) *'' Oncidium bifolium'' → '' Gomesa bifolia'' (Brazil to N. Argentina) *'' Oncidium blanchetii'' → '' Gomesa blanchetii'' (E. & S. Brazil.) *'' Oncidium brunleesianum'' → '' Gomesa echinata'' (Brazil - Rio de Janeiro) *'' Oncidium ciliatum'' → '' Gomesa ciliata'' (SE. Brazil) *'' Oncidium concolor'' → '' Gomesa concolor'' (Brazil to NE. Argentina) * Floral Morphology of an Oncidium Orchid

'' Oncidium cornigerum'' → '' Gomesa cornigera'' (SE. & S. Brazil to Paraguay) *'' Oncidium crispum'' → '' Gomesa imperatoris-maximiliani'' (SE. Brazil) *'' Oncidium croesus'' → '' Gomesa croesus'' (Brazil - Rio de Janeiro) *'' Oncidium dasytyle'' → '' Gomesa dasytyle'' (Brazil - Rio de Janeiro) *'' Oncidium divaricatum'' → '' Grandiphyllum divaricatum'' (SE. Brazil) *'' Oncidium flexuosum'' → '' Gomesa flexuosa'' (E. & S. Brazil to NC. Argentina) *'' Oncidium forbesii'' → '' Gomesa forbesii'' (Brazil - Minas Gerais) *'' Oncidium gardneri'' → '' Gomesa gardneri'' (Ecuador, SE. Brazil) *'' Oncidium hydrophilum'' → '' Gomesa hydrophila'' (Brazil to Paraguay) *'' Oncidium klotzschianum'' → '' Oncidium nebulosum'' (Costa Rica to Venezuela and Peru) *'' Oncidium longicornu'' → '' Gomesa florida'' (Brazil to NE. Argentina *'' Oncidium longipes'' → '' Gomesa longipes'' (Brazil to NE. Argentina) *'' Oncidium marshallianum'' → '' Gomesa marshalliana'' (SE. Brazil) *'' Oncidium micropogon'' → '' Gomesa micropogon'' (Brazil) *'' Oncidium pectorale'' → '' Gomesa pectoralis'' (Brazil - Rio de Janeiro) *'' Oncidium praetextum'' → '' Gomesa praetexta'' (SE. Brazil) *'' Oncidium pubes'' → '' Gomesa pubes'' (Colombia, SE. Brazil to NE. Argentina) *'' Oncidium raniferum'' → '' Gomesa ranifera'' (SE. Brazil) *'' Oncidium sarcodes'' → '' Gomesa sarcodes'' (SE. Brazil) *'' Oncidium uniflorum'' → '' Gomesa uniflora'' (SE. & S. Brazil) *'' Oncidium varicosum'' → '' Gomesa varicosa'' (Brazil to N. Argentina) *'' Oncidium venustum'' → '' Gomesa venusta'' (Brazil) File:Oncidium sphacelatum 3.jpg, ''Oncidium sphacelatum'' File:Oncidium Sharry Baby - smells like chocolate.jpg, ''Oncidium'' Sharry Baby smells like chocolate.

Nothogenera

Many hybrids have been created artificially involving species of ''Oncidium'', often with species of other genera. Named hybrid genera (nothogenera) are listed in the table below, together with their parent genera. , ''Cochlioda'' and ''Odontoglossum'' are included within ''Oncidium'', and ''Baptistonia'' within ''Gomesa'', so that nothogenus names which include these three genera are redundant.

References

* Harry Zelenko :The Pictorial Encyclopaedia of Oncidium (1997) * Koniger, W. 2003. New species of the genera Masdevallia, Oncidium and Sigmatostalix. Arcula no. 12: 298–311. *

External links

* * {{Authority control Oncidiinae genera Epiphytic orchids Taxa named by Olof Swartz