of M. concava. However, the lobing and callus is similar 
in both concepts. Specimens examined have the seta- 
ceous floral bracts attributed to M. concava. 
This species has been found in Mexico, Guatemala, 
Costa Rica and Panama where it is epiphytic on trees in 
forests from sea level up to 1200 meters altitude. 
Xylobium Powellii Schlechter in Fedde Repert. 
Beihefte 17 (1922) 66. 
Xylobium sublobatum Schlechter in Fedde Repert. 
Beihefte 19 (1928) 51. 
A comparison of an analytical drawing in the Ames 
Herbarium of the type of XY. sublobatum in the Schlechter 
Herbarium with an isotype of Y. Powellii reveals that 
they are conspecific. The lateral lobes of the lip of XY. 
Powellii are more pronounced than in X. sublobatum. 
Otherwise, the two concepts are identical. The trilamel- 
late dise of the lip is evident in both, and both have the 
characteristically short pseudobulb and inflorescence. 
This species is extremely close to XY. Tuerckhermiu 
Kriinzl. If it were possible to examine the type of that 
concept, we believe it would prove to be conspecific with 
X. Powellir. 
Xylobium Powellii has been found in Costa Rica and 
Panama where it grows on trees and stumps in forests 
up to 2000 meters altitude. 
Since Maaillaria, Camaridium and Ornithidium are 
now considered to be congeneric, the following nomen- 
clatorial changes for several Central American species 
are necessitated. 
Maxillaria bracteata (Sch/tr.) Ames & Correll comb. 
nov. 
Ornithidium bracteatum Schlechter in Fedde Repert. 
9 (1911) 217. 
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