The pseudobulbs are reduced. The obtuse, fleshy leaves are 9cm long. They are broadly elliptic to ovate-lanceolate.
The large, showy flowers grow basally on a short peduncle in a single-flowered to few-flowered raceme. They are white, or white covered with maroon dots. The petals and sepals are similar.
The long lip carries a short spur. This feature distinguishes the genus from other Oncidiinae, in which the spur is an extension of the column. The short column has a pair of apical wings on the stigma. The anther often bears minute papillae. There are two waxy pollinia, connected to elongate stipes.
Taxonomy
There is disagreement as to the taxonomic status of some species that were moved from Oncidium to Trichocentrum. Morphological characteristics of "typical" trichocentrums, such as being relatively small and squat with a short, few-to-several flowered inflorescence, contrasts sharply with the larger, heavier oncidiums with long, "mule-ear" leaves and showy, branched inflorescences with many flowers, or the "rat-tail" species with terete leaves.[citation needed]
While studies of molecular phylogeny has caused substantial reclassifications,[5] it is uncertain whether this new scheme will be widely adopted. As with many plants, hybridisation might heavily confound cladistic analyses, though the exact extent is unknown. Hybridisation of Trichocentrum with Oncidium has resulted in the hybrid genus × Trichocidium for example, and similar events in the past would result in unrealistic assessments of relationship based on molecular phylogenetic studies with too limited a scope.[citation needed]
In 2024, Trichocentrum was expanded to include the genera Grandiphyllum and Saundersia/[6] The expansion is accepted by Plants of the World Online.[4]
Trichocentrum species are highly appreciated by orchid growers; some consider them to be among the most beautiful orchids on earth. Culture of members of this genus is highly variable, ranging from the drought-tolerant and easy-to-grow T. tigrinum to smaller and more delicate species.
In cultivation they are subject to rot unless provided with conditions similar to those they experience in the wild. Extensive research into the ecological profiles of individual species may be required to achieve success cultivating them. Many species from Central America apparently endure a prolonged drought for at least part of the year, and have developed succulent leaves to deal with these conditions. Plants may shrivel quite severely without long-lasting injury.
Chemistry and use as entheogen
The Central and South American species Trichocentrum cebolleta (known formerly as Oncidium cebolleta) has been found to contain a variety of phenanthrenoids.[8] This species is of considerable ethnobotanical interest as one of only a handful of orchids reported to be used as an entheogens. T. cebolleta is used as a substitute for hikuli a.k.a. peyote (the hallucinogeniccactusLophophora williamsii) by the Tarahumara of Northern Mexico - a tribe noted for the large number of hallucinogenic plants which it uses in various shamanic and running-related practices. The combination of phenanthrenoid content and employment as entheogens in shamanic practices is to be found also in the Asiatic orchids Vanda tessellata and Dendrobium macraei (- known formerly as Ephemerantha macraei and Flickingeria macraei - see page Flickingeria). The orchidaceous genera Trichocentrum, Vanda and Dendrobium are all members of the subfamily Epidendroideae and are also placed currently in the subgroup/clade of Higher Epidendroids within the subfamily. Stermitz et al.,[9] however, do not report any evidence or suggest that the phenanthrenoids from Trichocentrum possess psychoactive properties.
Ackerman, J.D. and Chase, M.W. (2001): Notes on the Caribbean orchid flora, 4. More combinations in Trichocentrum and Cyrtochilum. Lindleyana16(4):225.
Chase, M.W. and Williams, N.H. (2001): Additional transfers to Trichocentrum Poepp. & Endl. and Otoglossum Garay & Dunst. (Orchidaceae: Oncidiinae). Lindleyana16(3): 218–219.
Pupulin, Franco (1995): A revision of the genus Trichocentrum (Orchidaceae: Oncidiinae). Lindleyana10(3):183–210. URL
Sandoval-Zapotitla, E. and Terrazas, T. (2001): Leaf anatomy of 16 taxa of the Trichocentrum clade (Orchidaceae: Oncidiinae). Lindleyana16(2): 81–93.
Williams, N.H., Chase, M.W., Fulcher, T., and Whitten, W.M. (2001): Molecular systematics of the Oncidiinae based on evidence from four DNA sequence regions: expanded circumscriptions of Cyrtochilum, Erycina, Otoglossum, and Trichocentrum and a new genus (Orchidaceae). Lindleyana16(2): 113–139.
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