base, 1-nerved, forming a short mentum with the column- 
foot, dorsally carinate with the keels extending onto the 
ovary. Petals much shorter than the sepals, very oblique- 
ly elliptic-lanceolate, about 3.5 mm. long and 1.1 mm. 
wide near the middle, acute or acuminate with more or 
less irregular upper margins, l-nerved. Lip lanceolate, 
in natural position with incurved lower margins and re- 
curved apex, when expanded about 8.5 mm. long and 
1.7 mm. wide below, cuneate at the base, the lower third 
dilated into indistinct broadly rounded lobules, the upper 
portion gradually narrowed to the obtuse apex, 3-nerved 
through the lower half; lamina fleshy-thickened near the 
base in the middle, densely minute-papillose above. Col- 
umn slender, slightly arcuate, dilated at the base, ter- 
minating in a trilobulate wing, about 2 mm. long, with 
a short broad fleshy foot. 
Pleurothallis tenuis is apparently allied to the Colom- 
bian P. intricata Lindl., but differs in the structure of 
the lip. 
Cuzco: F. L. Herrera 2157 (C. Bues coll.). (Type in U.S. Nat. 
Herb. No. 1423521). Ayacucuo: Aina, between Huanta and Rio 
Apurimac, at 750-1000 meters altitude, epiphyte in dense forest, May 
7,17, 1929, FE. P. Killip & A.C. Smith 22539. This collection, which 
consists of advanced specimens with withered flowers on the summit 
of rounded ovaries, shows one plant about 11 cm. high, with stem 
about 4 cm. long bearing six hirsute sheaths; another stem bears a 
leaf about 3.5 em. long and 1.1 cm. wide; one inflorescence is about 
8 em. long and bears eighteen flowers. 
Pleurothallis Vargasii C. Schweinfurth sp. nov. 
Herba robusta. Caulis crassus, vaginis duabus vel tri- 
bus laxis ornatus. Folium oblongo-ellipticum vel ovale, 
apice rotundatum vel leviter emarginatum, sessile vel 
subsessile, valde coriaceum. Inflorescentiae plures, erec- 
tae, folio subaequales vel paulo longiores, dense mul- 
tiflorae. Sepala intus dense pubescentia, extus leviter 
carinata. Sepalum dorsale ovato-oblongum, apice rotun- 
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