The concept P. rhizomatosa (of which I have seen iso- 
type material) is surely referable to P. macrorhiza, of 
which we have a record of the type. Its flowers appear 
to be of about the same size, and its petals are oblong- 
cuneate like those of P. macrorhiza rather than obovate- 
spatulate as described and figured for P. rhizomatosa. 
A Peruvian collection (Macbride & Featherstone 2455) 
is also referable to P. macrorhiza, but has larger (espe- 
cially broader) leaves and the obovate-spatulate petals 
described and figured for P. rhizomatosa. 
This species, described from and probably rather fre- 
quent in Ecuador, is now recorded from Peru. 
Pleurothallis semipellucida Reichenbach filius in 
Linnaea 22 (1849) 823—Lindley Fol. Orch. Pleurothal- 
lis (1859) 7, no. 27. 
Humboldtia semipellucida O. Kuntze Rev. Gen. Pl. 2 
(1891) 668. 
Pleurothallis complicata Rolfe in Mem. ‘Torr. Bot. 
Club 6 (1896) 121. 
An examination of isotype material of Plewrothallis 
complicata shows that it should not be separated from 
P. semipellucida. The single noteworthy difference is that 
typical P. semipellucida has petals which are distinctly 
clavate and more or less obtuse at the much-thickened 
apex (although they vary in degree even in a single col- 
lection), while those of P. complicata are linear and but 
very slightly broadened above. 
A large series of Peruvian collections reterable to P. 
semipellucida shows a range of petals varying from con- 
spicuously clavate and much-thickened to linear and 
scarcely dilated or thickened above. 
This species, described from Venezuela, occurs in ‘Trin- 
idad, appears to be frequent and widely distributed in 
Peru, and extends to Bolivia (as P. complicata). 
[ 177 | 
