Prosthechea

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Prosthechea
Prosthechea-cochleata.jpg
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.

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.[2] The status of Euchile species as sister to Prosthechea excluding Euchile was confirmed by Higgins in his doctoral dissertation in 2000.[3] 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][4]

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.[5]

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[edit]

Prostechea garciana

References[edit]

  • Higgins, W. E. (1997) [1998]. "A reconsideration of the genus Prosthechea (Orchidaceae)". Phytologia 82: 370–383. 
  • Higgins, W. E., van den Berg, C., Whitten, W. M. (2003). "A Combined Molecular Phylogeny of Encyclia (Orchidaceae) and Relationships within Laeliinae". Selbyana 23: 165–179. 
  • Van den Berg, C. (2001). "Nomenclatural notes on Laeliinae--III. Notes on Cattleya and Quisqueya, and a new combination in Prosthechea". Lindleyana 16 (3:): 142, 143. 
  • PIRES M.D.F.D.O.; SEMIR J.; PINNA G.F.D.A.M.D.; FELIX L.P. (November 2003). "Taxonomic separation of the genera Prosthechea and Encyclia (Laeliinae: Orchidaceae) using leaf and root anatomical features". Botanical Journal of the Linnean Society 143 (3): . 293–303. doi:10.1046/j.1095-8339.2003.00195.x. 
  • Chiron, G.R. (2003). "An Introduction to the Genus Prosthechea". The orchid Review 111 (1250). 
  • Chiron, G. R. (2005). "Contribution a l'etude de Prosthechea section Parviloba (Orchidaceae)". Richardiana 5 (3): 129–153.  (in French)
  • Pabst, G. F., J. L. Moutinho, and A. V. Pinto (1981). "An attempt to establish the correct statement for genus Anacheilium Hoffmanns. and revision of the genus Hormidium Lindl. ex Heynh.". Bradea 3: 173–186. 

Footnotes[edit]

  1. ^ a b Kew World Checklist of Selected Plant Families
  2. ^ C. L. Withner, Brassavola, Encyclia,and other genera of Mexico and Central America. The Cattleyas and their Relatives Timber Press, Portland, Oregon. 1998
  3. ^ reported in W. E. Higgins: "PROSTHECHEA A CHEMICAL DISCONTINUITY IN LAELIINAE", Lankesteriana 7(2003)39-41
  4. ^ Flora of North America v 26 p 613, Prosthechea Knowles & Westcott, Fl. Cab. 2: 111. 1838.
  5. ^ 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

External links[edit]