Taxon	Illustrator ⠉
	Brassia caudata Ionopsis utricularioides Macradenia lutescens Oncidium ensatum Trichocentrum undulatum Tolumnia bahamensis	Barbara Alongi Barbara Alongi Barbara Alongi Barbara Alongi Barbara Alongi Barbara Alongi

Herbs, epiphytic, lithophytic, or terrestrial, cespitose or creeping, sympodial. Roots numerous, white, velamentous. Stems highly reduced, rhizomatous, pseudobulbs, short-cylindric, laterally compressed, covered by scalelike sheathing bracts. Leaves deciduous, solitary, conduplicate, articulate; blade elliptic to broadly oblanceolate, large, fleshy, leathery, margins entire. Inflorescences axillary, from base of pseudobulb, racemes or panicles, loosely or densely few to many-flowered; floral bracts without sheathing base, ovate to linearlanceolate, small, apex acute. Flowers resupinate, generally large, fleshy, showy; sepals and petals spreading, distinct and free, often spotted; lip spotted or immaculate, unlobed to pandurate and 2–3-lobed; basal crest sometimes present, and if present variable in shape, often large, some species with slender spur formed by base of lip; column erect, winged; stigma simple, concave; anther operculate; pollinarium composed of small triangular to reniform viscidium, short convex stipe, and 2 obovoid pollinia. Fruits capsules, pendent, ellipsoid.

Distribution

Subtropical and tropical regions, North America, Mexico, West Indies, Central America, South America

Discussion

Species 54 (1 in the flora).

Most of the species included in this expanded concept of Trichocentrum, including the single species in the flora, languished in Oncidium for a long time even though the vegetative morphology and chromosome counts indicated that it might be a good genus, or that it should be segregated from Oncidium (M. W. Chase 1986; R. L. Dressler 1993). Need for segregation of the group was reaffirmed by plastid DNA work (M. W. Chase and J. D. Palmer 1992). Those data, however, did not clearly indicate how those elements of the “Lophiaris clade” should be classified. It was suggested that the mule-ear and rat-tailed oncidiums should be grouped together along with the genus Trichocentrum (R. L. Dressler 1993). Additional molecular work (N. H. Williams et al. 2001) reinforced that opinion, making the concept of Trichocentrum broader than that of either Lophiaris sensu G. J. Braem (1993) or Trichocentrum sensu F. Pupulin (1995).

Selected References

None.

Lower Taxa

Trichocentrum undulatum