TROPICAL AMERICAN ORCHIDS 
Pleurothallis Sanchoi Ames Sched. Orch. 4 (1923) 26. 
Plate 12: 1, column X 5. 2, lateral sepals X 3. 3, 
petal X 5. 4, dorsal sepal X 3. 5, labellum X 8. 6, leaf 
from Lankesier 482, about natural size. 
Pleurothallis stenostachya Reichh. f. var. Lankes- 
teri (Rolfe) Ames var. nov. 
Pleurothallis Lankesteri Rolfe in Kew Bull. (1914) 210. 
The variety differs from the species in having a deep 
crimson labellum. From available evidence it would seem 
that this variety is confined to Costa Rica. 
Plate 15: 1, flower X 11. 2, petal X 13. 3, labellum 
X 16. 4, lateral sepals X 9%. 
Pleurothallis trachychlamys Schitr. in Fedde Repert. 
Beihefte 17 (1922) 23. 
Plate 19: 1, (lower (one half removed) X 5%. 2, la¬ 
bellum X 10%. 3, column X 7%. 
Pleurothallis vinacea Ames Sched. Orch. 6 (1923) 69. 
Plate 13: 1, labellum with the lateral lobes in natural 
position X 5%. 2, labellum outspread X 5%. 3, lateral 
sepals X 2%. 4, column X 5%. 5, petal X 3. 6, dorsal 
sepal X 2%. 
Pleurothallis Williamsii Ames Orch. 7 (1922) 120. 
Plate 15: 1, flower X 5%. 2, labellum outspread X 9. 
3, petal X 8. 
Polystachya Powellii Ames sp. nov. Caules plus mi- 
nusve elongati, vaginis foliorum omnino obtecti. Folia 
ligulata, utrinque angustata, apice obtuse bilobulata. Pe- 
dunculus folia excedens, vaginis tubulatis obtectus. Racemi 
plures, breves, secus rachin communem dissiti, paniculam 
angustam laxam formantes. Sepala lateralia mentum for- 
mantia, ovata, acuta, concaviuscula. Sepalum dorsale ob- 
longum, acutum. Petala lineari-spathulata, uninervia. La¬ 
bellum e basi cuneata dilatatum, supra medium trilobatum; 
lobis lateralibus obtusis; lobo medio abrupte in apicem 
,31 
