DISA. 135 
to one or to two distinct glands, which lie at the apex of, or on the 
arms of the rostellum. Capsule oblong, clavate or linear, erect.— 
Terrestrial herbs with undivided sessile tubers; leaves appearing with 
or before the flowers; scape herbaceous or somewhat rigid, leafy, or 
with the leaves reduced to bracts or sheaths ; flowers solitary, loosely 
corymbose, racemose, or spiked, large or small. (Name unexplained ; 
it has been suggested from dis (dives), rich, in allusion to the magnifi- 
cence and beauty of the flower,—Disa uniflora, on which Berg founded 
the genus.) 
To this genus, as defined by Bentham (Gen. Plant., i., 680), 
I have in the present work added Lindley’s genera Schizodium and 
Monadenia. As thus constituted, it forms a large genus of more than 
one hundred species. I suppose the variety in the perianth to be only 
excelled, perhaps, by that of Habenaria or Catasetum, and to be 
scarcely equalled by that of any other genus in the vegetable world. 
Few systematic botanists, on seeing for the first time such species as 
D. grandiflora, D. tenuifolia, D. Harveiana, D. atricapilla, D. tenuis, 
D. fasciata, D. sagittalis, and D,. Charpentieriana, would doubt their 
representing so many distinct genera, or would suppose that they 
could be properly united. Yet a consideration of the whole of the 
species leads to the conclusion that they cannot be conveniently 
separated. 
A noteworthy characteristic of this genus is the degree of uniformity 
and comparative insignificance of the lip. Excepting in one group 
(Herschelia) of about twelve species, the lip is usually very small, and 
often much smaller than any of the sepals. In all these it is the odd 
sepal which, by the great variety in its shape and setting or position, 
and frequently by its large size, seems to fulfil the part which in many 
Orchids is played by the lp. 
The most salient characters available for divisions are :—1, the 
position of the parts of the flower resulting from the twisting or non- 
twisting of the ovary and pedicel; 2, the shape of the odd sepal and 
its position, whether erect or reclined; 8, the number of the glands of 
the pollinia, though this is often unstable; 4, the time of appearance 
of the leaves, and their structure. Based upon these, the following 
sections are here adopted, some from Lindley and others now proposed 
for the first time. 
§ 1. Monadenia, established as a genus by Lindley, is, as I have 
pointed out elsewhere, separable solely on the grounds of the caudicles 
of the pollinia terminating in a single gland, and of a slight modifica- 
tion of the rostellum. The former character is observable in the 
‘section Herschelia, where it is variable, as well as in the section 
Amphigena ; and the rostellum is too variable, from species to species 
