[Plate 21. j 
TIIE SESSILE ONCID. 
(ONCIDIUM SESSILE. 
A stove Epiphyte, from Peru, belonging to the Natural Order of Orchids. 
gpttifit Character. 
THE SESSILE ONCID.— Pseudo-bulbs 2-Ieaved, oblong, 
compressed, ribbed. Leaves strap-shaped, papery, blunt, 
shorter than the scape,which bears apanicled raceme. Sepals 
distinct and petals equal in size and form, all sessile. Lip- 
eared, dilated at the end and retuse; its re-entering angles 
slightly lobed ; the crest hollowed out, smooth, 3-lobed, 
with two small edges in front. Wings of the calyx short 
and truncated. 
ON CIDIUM SESSILE,— (Pentapetala macropetala) ; 
pseudobulbis diphyllis oblongis compressis costatis, foliis 
loratis pergameneis obtusiusculis scapo racemoso-panicu- 
lato brevioribus, sepalis distinctis petalisque oblongis 
obtusis planis sequalibus conformibus omnino sessilibus, 
labello auriculato apice dilatato retuso sinu sublobato, 
crista excavata laevi 3-loba antice bilamellata, columns 
alis brevibus truncatis. 
J^ native of the country at the back of Santa Martha, whence it was sent to His Grace the Duke 
of Northumberland by Mr. Purdie. It flowered at Syon in this last spring. 
It is nearly related to the little known Excavated Oncid (0. exematwm), a Permian plant formerly 
m the possession of Messrs. Loddiges ; but it is much handsomer and may be regarded as one of the 
best of the little group to which it belongs. The Excavated Oncid differs essentially in the following 
circumstances ; the flowers form a loose, and not a close or racemose panicle ; the sepals are 
narrower than the petals, not of the same breadth, they are distinctly stalked (unguiculate) not 
blunt lik 
with 
olumn are much larger, rounded and not truncate. 
Ihe habit of this species is that of the Lofty Oncid ( 0. aUimmum) on a small 
wings 
firm thin texture 
petal a 
Oncids j instead of which they sit close round 
unguis 
