Dimerandra Schltr. in Fedde, Rep. Beih. 17: 43, 1922. 



Sepals similar, spreading; lateral sepals oblique; all more or 

 less linear-lanceolate, acuminate. Petals spreading, more or less 

 rhombic to elliptic, often along one side the margin lobulate; lip 

 either free to base or laterally adnate basally to column, then 

 with a cuneate-flabellate blade; disc under column with a callus 

 of imbricating lamellae in three rows; on each side there is an 

 additional callose ridge. Column short, somewhat arcuate, with 

 two prominent lobes to the clinandrium, both of which are 

 externally keeled. Anther incumbent, small, completely hidden 

 within the lobes of the clinandrium, longitudinally septate. Pol- 

 linia four, compressed, inappendiculate. Ovary slender, pedi- 

 cellate. 



Epiphytic plants; roots flexuous, glabrous; stems caespitose, 

 erect, fleshy, leafy throughout, completely covered with thin, 

 imbricating leafsheaths, dry or old canes striate-sulcate; leaves 

 subcoriaceous, oblong-linear to ligulate, sessile, articulate with 

 leaf-sheaths; inflorescence terminal, 1-3, very short, 1-, 2-flow- 

 ered; flowers showy. 



Lectotype: Epidendrum Rimbachii Schltr., in hoc loco! 



Eight species distributed in Central America, from Mexico to 

 Panama, in northern and western tropical South America, from 

 the Guayanas to Peru, and along the edges of the Amazonian 

 Hyalea. 



KEY TO SPECIES 



1 . Flowers fleshy; petals broadly elliptic; fleshy ridges flanking 

 calli forked; column-ears ovate-lanceolate, acuminate 



D. carnosiflora 



la. Flowers delicate in texture; petals rhombic to lanceolate; 

 fleshy ridges flanking calli undivided; column-ears rectangu- 

 lar to transversely oblong 2 



2. Lip from a broad base abruptly rhombic to obtrapeziform 



in outline, widest at or below the base 3 



2a. Lip from a narrowly cuneate-unguiculate base obverse in 



outline, widest above the middle 4 



204 



