TROPICAL AMERICAN ORCHIDS 
bicarinale there, 3-nerved, minutely and densely papillose, 
especially the lower third, rounded at the apex, anterior 
margins minutely fimbriate, the nerves keeled on the under 
surface especially at the tip. Column 2.5-2.9 mm. long, with 
a broad petaloid wing which is sharply 3-toothed at the 
summit. 
Pleurothallis acrisepala is allied to P. Brighamii S. 
Wats., but is a larger plant with different sepals and lip. It 
also differs from P. pyrsodes Reichb. f. in having dissimilar 
sepals and lip. 
Panama, without exact locality, C. VV. Powell 420. 
(Type in Herb. Ames No. 29014.) 
Pleurothallis angusta A. & S. sp. nov. Herba medio- 
cris. Caulis monophyllus. Folium oblongum, acutum, basi 
late rotundatum, erectum, coriaceum. Pedunculi plures, uni- 
flori. Sepala lateralia in synsepalum ovatum omnino con- 
nata. Sepalum dorsale late oblongum, acutum. Petala fal- 
cato-linearia, apiculata, marginibus inferioribus conspicue 
erosis. Labellum oblongo-ovatum, crassum. 
Stem more than 10.7 cm. tall (incomplete in our speci¬ 
men), monophyllous, about 1.4 mm. in diameter. Leaf 
erect, oblong, 12.5 cm. long, 1.65 cm. wide, shortly acute 
with an obtuse tip, broadly rounded at the clasping base, 
coriaceous, the mid-nerve sulcate above and conspicuously 
carinate beneath. Peduncles several (about six), short, 
1-flowered, filiform, arcuate. Flowers medium-sized, perianth 
segments spreading. Lateral sepals connate into an ovate 
lamina 8.6-9.9 mm. long, about 5.1-6 mm. wide, acute, 
but with a rounded cucullate tip, dorsally bicarinate, very 
shortly connate at base with the dorsal sepal, prominently 
4-nerved with two faint nerves in the centre. Dorsal sepal 
broadly oblong-lanceolate or oblong, 9-10.5 mm. long, 
3.9-4.2 mm. wide, acute, 3-nerved, dorsally carinate. Petals 
linear-falcate, 6.1-6.6. mm. long, about 1.9 mm. wide below, 
acute, apiculate, margins erose-denticulate, the lower mar¬ 
gins conspicuously so, posteriorly round-auricled at the base, 
1-nerved, subcarinate especially at the apex. Labellum ob¬ 
long-ovate or Ungulate, cordate at the thickened base, 4-4.2 
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