Trichocentrum (abbreviated Trctm in horticulture) is a genus of epiphytic orchids in the family Orchidaceae, order Asparagales, commonly known as dancinglady orchids. It was first described by Eduard Friedrich Poeppig and Stephan Ladislaus Endlicher in 1836 and alone constitutes the Trichocentrum alliance, a distinct lineage within the subtribe Oncidiinae.
The genus is characterized by reduced pseudobulbs and obtuse, fleshy leaves that are broadly elliptic to ovate-lanceolate, reaching about 9 cm in length. Its large, showy flowers are borne basally on short peduncles in single- to few-flowered racemes. Flowers are typically white, or white marked with maroon dots; petals and sepals are similar in appearance. The defining morphological feature is the long lip bearing a short spur — unlike other Oncidiinae, where the spur is an extension of the column. The column bears a pair of apical wings on the stigma, and there are two waxy pollinia connected to elongate stipes.
As of 2025, Plants of the World Online recognizes approximately 101 species (plus natural and artificial hybrids), distributed in damp forest habitats from Mexico and Florida south to Argentina. In 2024, the genus was expanded to absorb Grandiphyllum and Saundersia, though this circumscription is not yet universally accepted. Hybridization between Trichocentrum and Oncidium has produced the registered hybrid genus × Trichocidium.
Etymology
The name Trichocentrum derives from Greek trich- (“hair”) and kentron (“spur”), referring to the slender, hair-like spur characteristic of the genus’s lip — a feature that distinguishes it from related Oncidiinae genera. The genus was named by Poeppig and Endlicher when they described it in 1836.
Distribution
Trichocentrum species inhabit damp forests across a broad neotropical range, from Mexico and southern Florida through Central America and the Caribbean, and into South America as far south as Argentina. The genus is primarily epiphytic, growing on trees in humid montane and lowland forest habitats throughout this range.
Taxonomy Notes
The circumscription of Trichocentrum has been contentious. Many species were transferred from Oncidium based on molecular phylogenetic evidence, though the morphological contrast between “typical” small, squat trichocentrums with short inflorescences and the larger, long-leaved oncidiums with branched, many-flowered inflorescences has fueled debate about whether the reclassification reflects natural groupings. Hybridization between the two genera — producing the hybrid genus × Trichocidium — may confound cladistic analyses. In 2024, Trichocentrum was further expanded to include Grandiphyllum and Saundersia; Plants of the World Online accepts this treatment, while World Flora Online does not.
Cultivation
Trichocentrum orchids are cultivated by orchid enthusiasts and available in the horticultural trade (abbreviated Trctm). They produce large, showy flowers and are grown as epiphytes under conditions typical for Oncidiinae alliance orchids — bright indirect light, good air circulation, and a well-draining bark or mounted substrate.
