TROPICAL AMERICAN ORCHIDS 
the fibrous remains of sheaths, the uppermost internodes more 
or less completely enveloped by a few rigid tubular imbricat¬ 
ing sheaths; nodes with a pair of subopposite leaves, the 
lower nodes producing a tuft of fibrous verrucose grayish 
roots. Leaves oblong-linear or oblong, up to 9 cm. long and 
9.5 mm. broad (the uppermost sometimes 1.5 cm. long and 
about 4 mm. wide), rounded and bilobed at apex, a minute 
apicule between the lobules, subsessile at base, coriaceous, 
the median nerve sulcate on the upper surface and carinate 
beneath. Flower apparently solitary at the summit of the 
uppermost internode. Pedicellate ovary slender, often 2 cm. 
long, concealed by a few imbricating sheaths. Lateral sepals 
ovate-lanceolate, 1.5 cm. long, 7.1 mm. wide below the 
middle, obtuse or acute, strongly concave below the middle, 
13-nerved, five of which are conspicuous. Dorsal sepal simi¬ 
lar, about 1.4 cm. long, 7.75 mm. wide below the middle. 
Petals similar, narrower, lanceolate, 1.35 cm. long, 5-6 mm. 
wide below the middle, obtuse, 5-7-nerved. Labellum in 
natural position strongly sigmoid; basal portion fleshy, nar¬ 
rowly and deeply concave, about 4 mm. long, subparallel 
with the column; central portion abruptly dilated into the 
lateral lobes between which are two approximate very fleshy 
keels; forward portion sharply reflexed and produced into a 
lamina; lateral lobes membranaceous, erect, 3-4 mm. long, 
embracing the summit of the column; anterior portion about 
8 mm. long, very broadly truncate and lightly retuse when 
spread out, in natural position oblong toward the base and 
cuneate-flabellate above, margins strongly plicate and cre- 
nate-erose. Column short, stout, about 7 mm. long, the con¬ 
cave anterior face continuous with the fleshy base of the 
labellum, a conspicuous conical boss in the middle, margin 
slightly dilated in the middle on each side; clinandrium 
irregularly crenate. 
There are no near relatives of Hexisea sigmoidea, but 
its habit recalls//, oppositifolia Reichb. f. 
Costa Riga, Santa Clara de Cartago, C. H. Lankester 
570, December 23, 1923. “Whole flower Flame Scarlet, PI. 
2 [Ridgway], semitranslucent or gelatinous, . . . —rare.” 
(Type in Herb. Ames No. 28120.) 
40 
