oblong-elliptic, rounded at base and apex, up to 12.5 
em. long and 8.8 cm. wide; petiole short, channelled, 
about 1 em. or less long. Inflorescence solitary, sub- 
equaling or exceeding the leaf, densely many-flowered 
above, enclosed at base by a conduplicate spathe about 
2.4 cm. or less long. Floral bracts conspicuous, spreading, 
infundibuliform. Flowers reddish yellow, with spreading 
segments. Sepals minutely cellular-ciliate. Dorsal sepal 
suborbicular-ovate, deeply concave, rounded to subacute 
at the apex, 3-nerved, about 7 mm. long and 5 mm. 
wide when expanded. Lateral sepals semiconnate or free, 
oblong-ovate, abruptly subacute, slightly oblique, con- 
cave below, about 7.8 mm. long and 4.8 mm. or less 
wide. Petals elliptic-oblong or broadly oblong, truncate 
to broadly rounded and bluntly subacute at the apex, 
3-nerved, about 5 mm. long and 8 mm. wide. Lip ob- 
long and tubular-concave with upcurved sides in natural 
position, 3-lobed and rhombic-obovate when expanded, 
cuneate below, 3-nerved, about 4.2-4.5 mm. long and 
4 mm. wide when spread out; lateral lobes shallowly 
semiobovate; mid-lobe transversely elliptic-oblong ; dise 
with a fleshy callus on each side just within the sinus 
between the lobes and with a lower semicircular callus 
near the concave base. Column small, somewhat dilated 
below, about 3.4 mm. high at the back, produced into 
a stout broad fleshy foot. 
This species is allied to Pleurothallis Vargasu C. 
Schweinf., but differs markedly in its more slender stems, 
narrower leaf, solitary inflorescence, glabrous sepals and 
the details of the lip. 
Cuzco: Prov. of Paucartambo, Pillahuata, at 2800 meters altitude, 
January 25, 1945, C. Vargas 4957 (Type in Herb. Ames No. 63340). 
Pleurothallis frutex Sci/tr. var. robusta C. 
Schweinfurth var. nov. 
[ 91 ] 
