Trichocentrum

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Trichocentrum
Trichocentrum haematochilum
Trichocentrum haematochilum
Plant Info
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Liliopsida
Order: Asparagales
Family: Orchidaceae
Subfamily: Epidendroideae
Tribe: Maxillariinae
Subtribe: Oncidiinae
Genus: Trichocentrum
Poepp. & Endl. 1836

Species
See text.

Trichocentrum is a small genus in the orchid family (Orchidaceae) with 65 species, many of which have been recently discovered or renamed (M.W.Chase & N.H.Williams, Lindleyana 16, 2001).

These epiphytic species are distributed in damp forests from Mexico to South America, but mostly in Venezuela, Colombia, Ecuador and Peru. They are considered by some to be among the most beautiful orchids on earth.

The pseudobulbs are reduced. The obtuse, fleshy leaves are 9 cm 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.

Culture of members of this genus is highly variable, ranging from the drought-tolerant and easy-to-grow Trichocentrum tigrinum to other, smaller species.

Trichocentrum species in cultivation 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.

Hybridisation of Trichocentrum with Oncidium has resulted in the hybrid genus Trichocidium.

There is disagreement as to the taxonomic status of some species that have recently been 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. While molecular phylogeny has caused Williams et al. (2001) to substantially reclassify a number of species, it is uncertain whether this new scheme will be widely adopted.


Species

 
Trichocentrum microchilum
 
Trichocentrum splendidum
 
Tiger-like Trichocentrum
Trichocentrum tigrinum

Natural hybrid

  • Trichocentrum × marvraganii (T. jonesianum × T. straceyi) (Bolivia)


References

  • 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). Lindleyana 16(2): 113-139.
  • Ackerman, J. D. and Chase, M. W. 2001. Notes on the Caribbean orchid flora, 4. More combinations in Trichocentrum and Cyrtochilum. Lindleyana 16(4): 225.
  • Chase, M. W. and Williams, N. H. 2001. Additional transfers to Trichocentrum Poepp. & Endl. and Otoglossum Garay & Dunst. (Orchidaceae: Oncidiinae). Lindleyana 16(3): 218-219.
  • Sandoval-Zapotitla, E. and Terrazas, T. 2001. Leaf anatomy of 16 taxa of the Trichocentrum clade (Orchidaceae: Oncidiinae). Lindleyana 16: 81-93.