PLEUROTHALLIS JOHNSTONII 



P. Johnstonii Ames Orchidace^, Fasc. ii. p. 271 (1908). 



Rhizome creeping, slender, clothed with tubular scarious sheaths. 

 Secondary stems erect or ascending, about 1.75 mm. long, or 

 shorter. Sheaths membranaceous, scarious, lax, truncate. Leaf 

 oblong-elliptic, retuse-apiculate at the apex or slightly triden- 

 tate, coriaceous, ± 5 mm. long, ± 3 mm. wide. Peduncle erect or 

 ascending, filamentous, graceful, few-flowered (with only one 

 flower expanded at a time?), 6-10 mm. long. Floral bracts 

 minute, pellucid, 1 mm. long. Lateral sepals lanceolate-acute, 

 1-nerved, free to the base, ±2.5 mm. long. Upper sepal lanceo- 

 late, prolonged into a slender filamentous tail, 1 cm. long includ- 

 ing the tail ; dilated part lanceolate, 2 mm. long. Petals linear- 

 lanceolate, 1-nerved, shorter than the sepals. Lahellum about 

 1 mm. long, ovate or oblong, obtuse, 3-nerved, fleshy, with a 

 fleshy callus at the base. Column 0.5 mm. long, margin of the 

 clinandrium entire. 



Venezuela : Alt. 600 m., Mt. San Juan, Island of Margarita, July 16, 1903, 

 J. R. Johnston (no. 238). 



The examination of another flower taken from the type spe- 

 cimen has made necessary several important alterations in the 

 original description, in which the dorsal sepal was inadvertently 

 confused with one of the lateral sepals. 



[27] 



