Within the

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 flowering ...

, ''Hormidium'' was originally a subgenus of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Epidendrum ''Epidendrum'' , abbreviated Epi in the horticultural trade, is a large neotropical genus of the orchid family. With more than 1,500 species, some authors describe it as a mega-genus. The genus name (from Greek ''επί, epi'' and ''δένδρο ...

'', but was later raised to a full genus. It is now considered not to be distinct from the genus ''

Prosthechea ''Prosthechea'' is a genus of flowering plants in the orchid family (Orchidaceae). The name is derived from the Greek word ''prostheke'' (appendix), referring to the appendage on the back of the column. Appendage orchid is a common name for this g ...

'', of which it is a

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

. Most of the species of ''Hormidium'' have been transferred to ''Prosthechea'', although others are now classified in ''

Encyclia :''Encyclia'' is also a Greek term for the Codex Encyclius ''Encyclia'' is a genus of orchids. The genus name comes from Greek ''enkykleomai'' ("to encircle"), referring to the lateral lobes of the lip which encircle the column. It is abbreviated ...

'', ''

Homalopetalum ''Homalopetalum'' is a genus of flowering plants from the orchid family, Orchidaceae. It contains 8 known species native to Central America, northern South America, Mexico and the West Indies. #'' Homalopetalum alticola'' (Garay & Dunst.) Soto ...

'', and ''

Lepanthes ''Lepanthes'' (from Greek "scaled-flower") is a large genus of orchids with about 800–1000 species, distributed in the Antilles and from Mexico through Bolivia (with very few species in Brazil). The genus is abbreviated in horticultural trade a ...

''.

Taxonomy

In 1841,

John Lindley John Lindley FRS (5 February 1799 – 1 November 1865) was an English botanist, gardener and orchidologist. Early years Born in Catton, near Norwich, England, John Lindley was one of four children of George and Mary Lindley. George Lindley w ...

used the name ''Hormidium'' for one of the subgenera into which he divided the genus ''

''. He described the subgenus as having

pseudobulb The 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 heteroblastic and ...

ous stems, sessile flowers and with the

lip The lips are the visible body part at the mouth of many animals, including humans. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech. Human lips are a tactile sensory organ, and can be ...

(labellum) of the flower joined (

adnate Adnate may refer to: * Adnation, in botany, the fusion of two or more whorls of a flower * Adnate, in mycology, a classification of lamellae (gills) * Conjoined twins Conjoined twins – sometimes popularly referred to as Siamese twins – are ...

) to the

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. ...

. Later, in 1861, Heinrich Reichenbach concluded that the subgenus ''Hormidium'' was superfluous. In 1883,

George Bentham George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studi ...

and

Joseph Hooker Joseph Hooker (November 13, 1814 – October 31, 1879) was an American Civil War general for the Union, chiefly remembered for his decisive defeat by Confederate General Robert E. Lee at the Battle of Chancellorsville in 1863. Hooker had serv ...

raised ''Hormidium'' to a full genus., p. 524f. They distinguished ''Hormidium'' from the other pseudobulbous species of ''Epidendrum'' with at least a partially adnate labellum, and specifically mentioned only four species, two of which are now retained in ''Epidendrum'', one which is now placed in ''Homalopetalum'', and one which is now placed in ''Lepanthes''. Because the genus ''Encyclia'' features non-adnate labella, and because the genus ''Prosthechea'' features labella which are only partially adnate (and therefore do not quite meet Lindley's criteria for ''Hormidium''), Bentham and Hooker's description is useful: :"The plant is a small

epiphyte An epiphyte is an organism that grows on the surface of a 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 epiphytes grow are called phoroph ...

. The pseudobulbs and rhizome are covered with membranaceous sheathes. The pseudobulb bears one or two small leathery or fleshy leaves. The flowers are small (or larger, in the case of ''Hormidium sophronitis''), born on a short raceme. The floral bracts are small. The sepals are of equal lengths, partially closed or completely open, the dorsal sepal free at the rear and the lateral sepals adnate to the base of the column forming a small "ladle". The petals are similar to the sepals or very narrow. The labellum is adnate to the column to its apex with completely erect lamina, either trilobate or lacking any divisions. The column is short with a dilated margin. The clinandrium is short and truncated. The terminal, operculate, slightly kidney-shaped anther leans against the column and carries four

pollinia A pollinium (plural 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 mil ...

. The flattened egg-shaped pollinia are distinct from each other." ''Hormidium'' is now considered not to be distinct from the genus ''

'', of which it is a synonym. Most, but not all, of the former species of ''Hormidium'' have been transferred to ''Prosthechea''.Search for "Hormidium",

Species and synonymy

The following species have at one time or another been placed in the genus ''Hormidium'' but are now placed in different genera: *''H. almasii'' (Hoehne) Brieger = ''

Prosthechea glumacea ''Prosthechea'' is a genus of flowering plants in the orchid family (Orchidaceae). The name is derived from the Greek word ''prostheke'' (appendix), referring to the appendage on the back of the column. Appendage orchid is a common name for this g ...

'' *''H. baculibulbum'' (Schltr.) Brieger = ''

Prosthechea vespa ''Prosthechea'' is a genus of flowering plants in the orchid family (Orchidaceae). The name is derived from the Greek word ''prostheke'' (appendix), referring to the appendage on the back of the column. Appendage orchid is a common name for this g ...

'' *''H. boothianum'' (Lindl.) Brieger = ''

Prosthechea boothiana ''Prosthechea'' is a genus of flowering plants in the orchid family (Orchidaceae). The name is derived from the Greek word ''prostheke'' (appendix), referring to the appendage on the back of the column. Appendage orchid is a common name for this g ...

'' *''H. brassavolae'' ( Rchb. f.) Brieger = ''

Prosthechea brassavolae ''Prosthechea brassavolae'' is a species of orchid native to Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia t ...

'' *''H. caetense'' Bicalho = ''

Prosthechea caetensis ''Prosthechea'' is a genus of flowering plants in the orchid family (Orchidaceae). The name is derived from the Greek word ''prostheke'' (appendix), referring to the appendage on the back of the column. Appendage orchid is a common name for this g ...

'' *''H. calamarium'' (Lindl.) Brieger = ''

Prosthechea calamaria ''Prosthechea'' is a genus of flowering plants in the orchid family (Orchidaceae). The name is derived from the Greek word ''prostheke'' (appendix), referring to the appendage on the back of the column. Appendage orchid is a common name for this g ...

'' *''H. coriaceum'' Brieger = ''

'' *''H. faresianum'' Bicalho = ''

Prosthechea faresiana ''Prosthechea'' is a genus of flowering plants in the orchid family (Orchidaceae). The name is derived from the Greek word ''prostheke'' (appendix), referring to the appendage on the back of the column. Appendage orchid is a common name for this g ...

'' *''H. faustum'' (Rchb.f. ex Cogn.) Brieger = ''

Prosthechea fausta ''Prosthechea'' is a genus of flowering plants in the orchid family (Orchidaceae). The name is derived from the Greek word ''prostheke'' (appendix), referring to the appendage on the back of the column. Appendage orchid is a common name for this g ...

'' *''H. gilbertoi'' (Garay) P.Ortiz = '' Prosthechea gilbertoi'' *''H. glumaceum'' (Lindl.) Brieger = ''

'' *''H. guttatum'' (A. Rich. & Galeotti) Brieger = '' Prosthechea guttata'' *''H. hioramii'' Acuna & Roíg = '' Prosthechea pygmaea'' *''H. humile'' (Cogn.) Schltr. = '' Prosthechea pygmaea'' *''H. ionocentrum'' (Rchb. f.) Brieger = '' Prosthechea ionocentra'' *''H. leochilus'' (Rchb.f.) B.D.Jacks. = '' Homalopetalum leochilus'' *''H. miserum'' (Lindl.) Benth. & Hook.f. ex Hemsl. = '' Epidendrum miserum'' *''H. pseudopygmaeum'' Finet = '' Prosthechea pygmaea'' *''H. pulchellum'' (Sw.) Benth. & Hook.f. ex B.D.Jacks. = '' Lepanthes pulchella'' *''H. pygmaeum'' (Hook.) Benth. & Hook.f. ex Hemsl. = '' Prosthechea pygmaea'' *''H. racemiferum'' (Dressler) Withner & P.A.Harding = '' Prosthechea racemifera'' *''H. rhynchophorum'' (A.Rich. & Galeotti) Withner & P.A.Harding = '' Prosthechea rhynchophora'' *''H. serpens'' (Lindl.) Benth. & Hook.f. = '' Epidendrum serpens'' *''H. sessiliflorum'' () Pabst, Moutinho & A.V.Pinto = '' Prosthechea sessiliflora'' *''H. sophronitis'' (Linden & Rchb.f.) Benth. & Hook.f. = '' Epidendrum sophronitis'' *''H. tripterum'' (Brongn.) Cogn. = '' Prosthechea pygmaea'' *''H. uniflorum'' (Lindl.) Heynh. = '' Prosthechea pygmaea'' *''H. variegatum'' Brieger = ''

'' *''H. virens'' Brieger = '' Encyclia diurna'' *''H. widgrenii'' (Lindl.) Brieger = '' Prosthechea widgrenii''

References

{{reflist Epidendreae * Prosthechea Encyclia Lepanthes Historically recognized angiosperm genera