Prosthechea


Prosthechea is a genus of flowering plants in the orchid family. The name is derived from the Greek word prostheke, referring to the appendage on the back of the column. Appendage orchid is a common name for this genus. Prosthechea is abbreviated Psh. in the horticultural trade.

Morphology

The roots of all Prosthechea species possess a velamen differentiated into epivelamen and endovelamen. Flavonoid crystals were observed in both the roots and leaves. The erect stems form flattened or thickened pseudobulbs. There are 1 to 3 terminal, sessile leaves. The leathery blade is ovate to lanceolate.
The flowers form an apical, paniculate raceme with a spathe at the base of the inflorescence. There is a great variety in the flowers of this genus. They may be attached to the stem by a peduncle or they may be sessile. They can flower on the raceme at the same time or successively. They can be resupinate or non-resupinate. Prosthechea flowers are unique among the Laeliinae in producing fluorescent flavenoid crystals when preserved in ethanol with 5% sodium hydroxide.
The sepals are almost equal in length, while the petals can be much slender. The lip is pressed closely to half of the column and shows a callus. The column is 3- to 5-toothed at its top.
There are four, almost equal pollinia with an inverted egg shape. There are four stalks in two pairs. The beak is entire, curved into a half circle and covered with viscous glycoside crystals.
The fruits consist of ellipse-shaped to egg-shaped, 1-locular, 3-winged capsules.

Taxonomy

The genus Prosthechea has only recently been reestablished by W. E. Higgins as a distinct genus. Two species were later transferred to Euchile by Withner in 1998. The status of Euchile species as sister to Prosthechea excluding Euchile was confirmed by Higgins in his doctoral dissertation in 2000. Previously, the species had been included in different genera : Anacheilium, Encyclia, Epidendrum, Euchile, Hormidium and Pollardia. The status as genus was confirmed by recent data, based on molecular evidence and plastid .

Distribution

This is a neotropical epiphytic genus, widespread across much of Latin America from Mexico to Paraguay, as well as in Florida and the West Indies.

Species

, Plants of [the World Online] accepts the following species:

Natural Hybrids