310 ` MR. H. N. RIDLEY’S REVISION OF THE 
stem, swollen after flowering into a pseudobulb and covered ` 
with one or more loose white membranous sheaths. The rhizome 
from which these pseudobulbs rise is usually very short, and 
emits but few roots. It is never so long as it 4s in several 
Liparids, such as Z. nepalensis. Microstylis commelinifolia has 
creeping stems entirely covered with alternate leaves, from the 
axils of which the scapes arise. It grows in thick masses, and, 
as its name denotes, resembles much a Commelinaceous plant. 
M. caulescens has also a creeping or prostrate stem covered 
with narrow suberect leaves, quite unlike anything else in the 
genus. 
Leaves.—The number of leaves on a plant varies from one to ten. 
The small green-flowered Dienias of South America possess no more 
than a single leaf, though the sheaths of the stem are frequently 
green and foliaceous. Many species have two leaves, which are 
often a little distant apart. In M. Rheedii and some others the 
more numerous leaves are scattered along the whole length of 
the erect stem ; but usually in the Orepidium section the leaves 
are clustered in a whorl at the top of the stem, which is covered 
below by mere sheaths. In M. commelinifolia and M. caulescens, 
as has been said above, the long stems are entirely covered with 
numerous small leaves. The form of the leaves is elliptic, ovate, 
cordate, or lanceolate, with a sheath at the base, between which 
and the lamina there is often a short petiole. The texture is 
thin and membranous, the edges often crisped, especially in 
the section Crepidium, in which also they are commonly very 
oblique. When there are several leaves, they are usually very 
unequal in size and often dissimilar in shape, the lower ones being 
much smaller, and often rounder and blunter than the upper 
ones. Some species of the section Crepidium, especially those 
from Borneo and the neighbouring islands, are remarkable for 
the beautiful colouring of their leaves. M. metallica has its 
leaves, pseudobulb, and scape of a dark purple-red colour highly 
polished. In M. calophylla the centre of the leaf is olive-brown, 
and the edge bright green with transverse streaks of olive- 
brown. 
The scape is usually erect and slender, often angled and shortly 
winged ; the lower part (usually from a third to a half) is nude, and 
above the flowers are arranged in alax or compact raceme or 
spike, or, as in the section Umbellulate, in an umbel at the top of 
an entirely nude stem. In the section Pedilea the pedicels 
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