Prosthechea

Prosthechea
Prosthechea cochleata
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Epidendroideae
Tribe: Epidendreae
Subtribe: Laeliinae
Alliance: Epidendrum
Genus: Prosthechea
Knowles & Westc., 1838
Type species
Prosthechea glauca
Knowles & Westc. - Floral Cabinet 2: 111-112. 1838.
Species

About 100 species - See text

Synonyms[1]
  • Epithecia Knowles & Westc., illegitimate superfluous name
  • Hormidium Lindl. ex Heynh.
  • Anacheilium Hoffmanns.
  • Epicladium Small
  • Euchile (Dressler & G.E.Pollard) Withner
  • Pseudencyclia Chiron & V.P.Castro
  • Panarica Withner & P.A.Harding
  • Pollardia Withner & P.A.Harding

Prosthechea is a genus in the orchid family (Orchidaceae). The name is derived from the Greek word prostheke (appendix), referring to the appendage on the back of the column. Appendage orchid is a common name for this genus.[2]

The genus Prosthechea has only recently (1997; published in 1998) been reestablished by W. E. Higgins as a distinct genus (see references). Two species were later transferred to Euchile (E. citrina and E. mariae) by Withner in 1998.[3] The status of Euchile species as sister to Prosthechea excluding Euchile was confirmed by Higgins in his doctoral dissertation in 2000.[4] 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 (nuclear (nrITS) and plastid (matK and trnL-F) DNA sequence data) (W. E. Higgins et al. 2003)

This a neotropical epiphytic genus, widespread across much of Latin America from Mexico to Paraguay, as well as in Florida and the West Indies.[1][5]

The roots of all Prosthechea species possess a velamen (a thick sponge-like covering) 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. (Euchile leaves are softer and thinner than other Prosthechea leaves.)

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 may be sessile. They can flower on the raceme at the same time or successively. They can be resupinate or non-resupinate (as in Prosthechea cochleata). Prosthechea flowers are unique among the Laeliinae in producing fluorescent flavenoid crystals when preserved in ethanol with 5% sodium hydroxide.[6]

The sepals are almost equal in length, while the petals can be much slender. The lip is pressed closely (adnate to proximal) to half of the column and shows a callus (a stiff protuberance). 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 (or caudicles) in two pairs. The beak is entire, curved into a half circle and covered with viscous glycoside crystals.

The fruits consists of ellipse-shaped to egg-shaped, 1-locular, 3-winged capsules.

Species

Prostechea garciana

References

Footnotes

  1. 1 2 Kew World Checklist of Selected Plant Families
  2. ↑ "Prosthechea". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 14 October 2015.
  3. ↑ C. L. Withner, Brassavola, Encyclia, and other genera of Mexico and Central America. The Cattleyas and their Relatives Timber Press, Portland, Oregon. 1998
  4. ↑ reported in W. E. Higgins: "PROSTHECHEA A CHEMICAL DISCONTINUITY IN LAELIINAE", Lankesteriana 7(2003)39-41
  5. ↑ Flora of North America v 26 p 613, Prosthechea Knowles & Westcott, Fl. Cab. 2: 111. 1838.
  6. ↑ W. E. Higgins, "PROSTHECHEA A CHEMICAL DISCONTINUITY IN LAELIINAE", Lankesteriana 7(2003)39-41, available online at http://www.jardinbotanicolankester.org/lankesteriana/Lankesteriana%20vol.%203.%202003/Lankesteriana%20N%207/Numeroporsecciones/17%20Higgins.pdf
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