TROPICAL AMERICAN ORCHIDS 
Plant very small, 7-8 cm. tall. Roots numerous, fibrous, 
flexuous, glabrous, slender. Secondary stems monophyllous, 
up to 3 cm. long, very slender, somewhat flattened above, the 
basal half with two approximate imbricating scarious 
sheaths. Leaf erect, oblong-elliptic, 2.25-3.1 cm. long, 
6-7.5 mm. wide, obtuse, coriaceous, with minutely erose 
margins which are strongly revolute in the dried state, the 
mid-nerve prominently carinate beneath. Inflorescences 
one to three, much exceeding the leaf, up to 5.8 cm. long. 
Peduncle filiform, clasped at the base by a small membra¬ 
naceous sheath and above by about two remote inconspicu¬ 
ous infundibuliform sheaths. Raceme more or less arcuate, 
2- 6-flowered; floral internodes 4-5 mm. long. Floral bracts 
minute, infundibuliform. Flowers relatively large. Lateral 
sepals either connate nearly to the apex or apparently free 
almost to the base, narrowly lanceolate, about 8.9 mm. long, 
1.9 mm. wide below, gibbous at the base, dorsally carinate 
with the keel produced into an apical mucro, 3-nerved. 
Dorsal sepal lanceolate-oblong, 9 mm. long, 2 mm. wide, 
acute and dorsally mucronate at the tip, prominently keeled 
below the middle, concave, 3-nerved. Petals much smaller, 
narrowly lanceolate, about 4 mm. long, 1 mm. wide, acu¬ 
minate, 1-nerved. Labellum obovate in outline, about 3 mm. 
long including the claw; claw narrow, 1.15 mm. long, grad¬ 
ually dilated from a very narrow base, a minute rounded- 
triangular auricle in the middle of each side; lamina broadly 
ovate, about 1.7 mm. wide, rounded at the apex, with erose 
margins, constricted near the cordate base to form small 
suborbicular lobules. Disc 3-nerved, indistinctly thickened 
on each lateral nerve in the middle. Column short, broadly 
winged above, 2.7 mm. long including the wing, which is 
3- lobed with the apical lobe quadrate and dentate. Column- 
foot short and stout. 
Pleurothallis parvula is allied to P. alpestris (Sw.) Lindl., 
but differs in the smaller slightly erose leaves and more 
ovate, not ligulate, lip. P. trichophora Lindl. has much 
smaller flowers and longer racemes. [Plate 23: habit life 
size, i, column X 4 3^. 2, labellum, three-quarter view X 
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