Observation: From the closely related O. chimborazoénse this new 
species is readily distinguishable by the 2-leaved pseudobulbs and the 
rhombic lip which is approximately as long as wide. The sepals and 
petals are maroon inside, much paler and suffused outside; the lip is 
white with heavy crimson blotches on the basal half especially on the 
lateral lobes; the callus is orange. 
ACKNOWLEDGMENTS 
The steady cooperation of my colleagues at the Orchid 
Herbarium of Oakes Ames, and especially the guidance 
of Dr. Leslie A. Garay, have been a continuous inspira- 
tion throughout the preparation of thisstudy. Their help 
is deeply appreciated. My special thanks to Dr. Peter 
Taylor, the Orchid Herbarium, Royal Botanic Gardens 
and to Dr. Luciano Bernardi, Conservatoire et Jardin 
Botaniques, Geneve, for their kind cooperation in pro- 
viding specimens and drawings of types. For permission 
to reproduce their color slides so essential to this study 
I am indebted to Mr. Gilberto Escobar-R, Mr. Rodrigo 
Escobar-R, Dr. George Kennedy and Mrs. Henry T. 
Northen. The publication of color plates was made possi- 
ble through the generosity of Mr. Maurice Tl’. Freeman, 
Mr. Walter Hunnewell, Mr. and Mrs. Lee B. Kuhn, 
the Lear Siegler Foundation, Mrs. Henry 'T. Northen, 
Mr. Robert M. Scully, Sr., Mr. Richard Seifert and 
Mr. Robert G. Stone. Their thoughtfulness and help 
are sincerely acknowledged. ‘To Miss Gertrude Ahern 
I am grateful for the dedicated attention given by her 
to this paper. 
[ 167 ] 
