TROPICAL AMERICAN ORCHIDS 
Pleurothallis crassilabia A. & S', sp. nov. Rhizoma 
repens. Caules secundarii monophylli, triquetri. Folium 
ovatum vel oblongo-ovatum, basi cordatum. Inflorescentia 
singula, folii dimidium aequans. Flores paullo aperti. Sepala 
lateralia in laminam latam bifidam connata, mentum for- 
mantia. Sepalum dorsale oblongo-lanceolatum, superne 
paullo latius. Petala minuta, spathulata, superne lacerato- 
serrata. Labellum in positu naturali oblongo-cuneatum, apice 
rotundatum. Columna minor, crassa. 
Plant medium-sized, 11.5 to about 23 cm. tall. Rhizome 
creeping, 2.5-3 mm. in diameter, concealed by castaneous 
membranaceous imbricating sheaths which wither away in 
anthesis. Roots fibrous, glabrous, longitudinally sulcate 
in the dried plant, for the most part issuing from the rhizome 
at the base of the secondary stems. Secondary stems stout, 
monophyllous, triquetrous, 6-17 cm. long, gradually broad¬ 
ened and flattened (i.e. with broader wings) toward the 
apex, with several imbricating membranaceous sheaths or 
remains of sheaths at base. Leaf sessile, ovate to oblong- 
ovate, shortly cordate, 6-9 cm. long (from the base of the 
short auricles to the apex of the blade), 2.6-4.6 cm. wide 
below the middle, coriaceous, acute or acutish, inserted 
diagonally on the stem. Inflorescence solitary, about half the 
length of the leaf, about 3 cm. long; rachis floriferous nearly 
to its base, with a small conduplicate coriaceous sheath at 
the base. Flower fleshy in texture; perianth campanulate. 
Lateral sepals connate into an ovate lamina which is 9.5 mm. 
long, about 6 mm. wide, sharply bidentate from the apex 
to above the middle, 7-nerved, bicarinate on the outer sur¬ 
face (sharply so above). Dorsal sepal oblong-lanceolate, 
slightly broader above, 9-10 mm. long, about 3.2 mm. wide 
above the middle, acute, strongly concave below, 3-nerved. 
Petals much smaller, spatulate, with the upper margins 
deeply lacerate-serrate on each side, about 3 mm. long and 
1.6 mm. wide above, obliquely inserted on the lateral sepals 
at the base, obtuse at the apex, 1-nerved, Labellum very 
fleshy, oblong-cuneate in natural position because of the 
erect tubular involute basal margins; lamina 5-5.4 mm. long, 
2.3 mm. wide above the middle, oblong when forcibly spread 
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