TROPICAL AMERICAN ORCHIDS 
semiorbicular in outline, sharply 3-lobed in front, 8 mm. 
long, 11.1 mm. wide across the spreading side lobes; claw 
minute; lateral lobes relatively large, broadly falcate- 
triangular with the outer margins rounded, the tips acute 
and the anterior margins undulate-truncate; middle lobe 
much smaller, ovate-triangular, scarcely surpassing the side 
lobes, acutish, concave by reason of folds of the disc at each 
sinus. Disc with a cluster of digitiform tubercles near the 
base in front of which there is a semilunate lamella which is 
tridentate in front and irregularly dentate on the sides. 
Column short, stout, about 7.5 mm. long. 
Maxillaria semiorbicularis appears to be allied to 
CamaridiumBradeorum Schltr., but has smaller leaves, mono- 
phyllous pseudobulbs, and different mid-lobe of lip. 
The name is in allusion to the shape of the labellum. 
Costa Rica, Province of San Jose, La Hondura, Paul 
C. Standley 36247, March 2-4, 1924. 1300-1700 metres al¬ 
titude. “On tree; flowers faded.” (Type in Herb. Ames No. 
29017.) 
Maxillaria vagans A. & S. sp. nov. Herba caulescens, 
paullo ramosa. Caulis basibus foliorum arete imbricanti- 
bus omnino obtectus. Pseudobulbi rari, valde complanati, 
monophylli. Folia oblonga, apice abrupte rotundata. Fiores 
singuli, ex axillis orientes. Perianthium patens. Sepala lat- 
eralia oblanceolato-oblonga, acuta. Sepalum dorsale ellip- 
tico-oblongum, valde acutum. Petala oblongo-oblanceolata, 
acuta. Labellum distincte trilobatum, expansum pandu- 
ratum; lobi laterales parvi, auriculiformes; lobus medius 
major, subtus carinatus. Columna parva, crassa. 
Plant caulescent. Stem stout, entirely invested by dis¬ 
tichous closely imbricating sheaths and leaf-bases, with 
several short branches which are about 7 cm. or less long; 
the lower portion of the stem (in our specimen) with numer¬ 
ous fibrous, flexuous, glabrous roots. Pseudobulbs of the 
main stem 6-7 cm. apart, monophyllous, more or less ellip¬ 
soid, strongly complanate and coarsely rugose in the dried 
state, about 3 cm. long. Leaves oblong, spreading; the larger 
ones 4.6-13.5 cm. long, 1.15-2.6 cm. wide, abruptly rounded 
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