213 
CATASETUM semiapertum. 
Greenish-flowered Catasetum. 
GYNANDRIA MONANDRIA— Nat. Ord. ORCHIDS^. 
Gen. Char. — Cor. petalis subaequalibus ; labello saccato-concavo. Columna 
bicornis ; cornua retrorsa, filiformia arcuato-conniventia. Anthera oper- 
culata, columnae interne infra apicem insidens. Pollinia duo, postice bi- 
loba V. sulcata ; caudicula maxima, demum elastice dissiliente, glandula 
cartilaginea, glutinosa, subquadrata. 
Catasetum semiapertum ; spica compacta foliis breviore, petalis paten- 
tibus subsecundis lato-ovatis concavis, labello ore contracto integro, 
lateribus minute denticulatis. 
The nature of the hulbs and leaves of this plant is so similar to those of Ca- 
tasetum tridentatum, figured in this work, that it is needless to repeat 
their description. 
The scape springs from the base of the bulb, and, including the flowers, is 
much shorter than the leaves. These flowers are collected into a dense 
ovato-globose spike ; each of them smaller than in C. tridentatum, Jlori- 
bundum and ClaveriJigii, and larger than in C. Hookeri of Lindley. The 
petals are of a pale greenish-yellow, concave, directed to one side, point- 
ing downwards, so as to leave the lip, which constitutes the upper part 
of the flower, quite exposed. The lip is a pale and delicate green, with- 
in greenish-purple, very thick and fleshy, forming a deep hollow, ovate 
and very obtuse pouch ; the mouth much contracted, the front part 
quite entire and yellow, the sides furnished with minute, teeth-like ci- 
liae. Column and Anther exactly the same as in C. tridentatum and Jlori- 
bundum; but the pollen-masses are much more oblong, and of a deeper 
orange colour. 
Different as I am satisfied is this species from all those 
hitherto described and f gured, yet it is scarcely possible to de- 
fine these differences in words. The petals come nearest in 
shape to those of C. Claveringii and C.jioribundum, being 
much broader than in C. tridentatum. The Up is distinguished 
VOL. III. 
