In dried specimens the fleshy labellum becomes flat- 
tened and more or less rounded at the tip (ef. text figure). 
In its natural condition the labellum is strongly concave, 
with the lip more or less acute and sharply bent upward, 
resembling Stelis rubens Schltr. 
In 1928, Schlechter described a Costa Rican species 
naming it Stelis cyclopetala. In his observations regard- 
ing the distinctive character of the flower, he emphasized 
the strikingly tall column as being twice longer than the 
petals. As close allies of his new species he referred to 
S. pusilla HBK., and S. angustifoha HBK. Yet he made 
no mention of S. ovatilabia Schltr. which stands out dis- 
tinctly among Middle American species of the genus in 
having an extraordinarily elongated column. WS. cyclopet- 
ala is so similar to S. ovatilabia, differing from it chiefly 
in having more membranaceous petals, that there is every 
reason to suspect that Schlechter simply overlooked his 
earlier species when he proposed anew one. Perhaps the 
difference between the petals might be used to differen- 
tiate the Costa Rican JS. cyclopetala as a variety of JS. 
ovatilabia, yet this would seem to be unwise in view of 
our present knowledge of the peculiarities of Stelis. The 
type of WS. cyclopeta/a is a diminutive plant scarcely 6 ¢m. 
tall, but the tendency toward great variation in the vege- 
tative proportions of species of Stelis indicates the need 
for caution in using size of stems and leaves as specific 
characters. Schlechter made sketches of the labellum to 
show his conception of its structure and these sketches 
conform to my camera lucida drawings made from the 
types. In the illustrations prepared for this paper by 
Blanche Ames, the labellum of 8. cyclopetala appears to 
be conspicuously auriculate while the labellum of S. ovati- 
labiais exauriculate. This difference, however, is apparent 
rather than real, because a slight compression of the label- 
lum at the base in herbarium specimens of WS. ovatilabia 
[ 164 | 
