3. Petals obovate-oblanceolate; lip rhombic to obscurely 3- 



lobed, lateral lobes rounded, midlobe terminal, transversely 

 quadrate-oblong, truncate in front D. stenopetala 



3a. Petals broadly rhombic; lip obtrapeziform, sinuously bilobed 



in front with a small apicule D. latipetala 



4. Lip free to base, bilobed to retuse; callus without a central 



row of lamellae; anther with three horn-like protuberances 



D. buenaventurae 



4a. Lip laterally adnate to base of column; entire or subtrun- 



cate to somewhat retuse; callus with a central row of lamel- 

 lae; anther without horns 5 



5. Lateral rows of callus fleshy, entire, keel-like, terminating in 



a few imbricating lamellae 6 



5a. Lateral rows of callus not keel-like, but composed of 



numerous imbricating lamellae almost to base 7 



6. Leaves linear-oblong, grass-like, 3-4 mm. wide; flowers 



thin, diaphanous; floral segments more than 10 mm. long; 

 lateral sepals with a prominent, horn-like mucro; anterior 

 margin of lip serrate-denticulate D. Rimbachii 



6a. Leaves linear-lanceolate, 6-7 mm. wide; flowers thin but 



firm in texture, not diaphanous; floral segments less than 10 

 mm. long; lateral sepals without a mucro; anterior margin of 

 lip entire D. tenuicaulis 



7. Three rows of callus united into transverse plates at apex in 



front of which there are a few, free-standing lamellae; 

 columnar ears transversely oblong, acute to obtuse 



D. elegans 



7a. Three rows of callus free from one another at apex, 



although they may be convergent at tip without accessory 

 lamellae; columnar ears subquadrate to rounded, often with 

 cellular margins D. emarginata 



Dimerandra buenaventurae (Krzl.) Siegerist, comb. nov. 



Basionym: Telipogon buenaventurae Krzl. in Ann. Naturhist. 

 Hofmus. Wien33: 35, 1919. 



Type: Colombia. Dept. Valle, near Buenaventura. Klaboch 

 Ail. (W!) 



205 



