INTRODUCTION. 111 
tribe Weottiee into two tribes, which we have named Listereae and Goodyercae. 
Іп all these changes Mr. Pantling and myself are in agreement. We are both 
strongly of opinion that, in limiting the larger groups, it is (as far as the Sikkim 
species go) the safest course to assign a supreme value to the structure and 
appendages of the pollen masses. In working with fresh specimens we have found 
that, in the genera which we have included in the old tribe Malazideae, the 
pollinia have absolutely no caudicle and no gland; and that, in the majority of 
cases, they are perfectly free from each other; in only a very few, viz., in three 
species of Cirrhopetalum and in the single species of Diglyphosa, being attached by 
their bases to a ball of translucent substance. In the genera which we have 
arranged in the tribe Hpidendreae the pollen masses, on the other hand, are attached, 
either by their backs or by their bases, to a single or double translucent appendage, 
but have no gland derived from the stigma. It may be that this limitation will not 
be found to answer in the South American Lpidendreae ; and it is also possible that, 
from the extreme delicacy of the translucent appendages, the character may be one 
difficult to work in the Herbarium. However, as the present work professes to 
be based on dissections of living, and not on those of dried specimens; and, moreover, 
as the polliniar differences are accompanied by certain differences in the facies of 
the vegetative organs, we feel bound to give full prominence to them. And in 
doing so we are, as already indicated, only returning to the lines followed by thas 
great orchidologist, John Lindley. Тһе tribe Zpidendreae passes into Vandeae by a 
transition suite of five genera (Zipularia, Monomeria, Acrochene, Agrostophyllum, 
and a new one which we have named Ritaia), in all of which the polliniar appendages 
are attached to a gland the origin of which from the stigma is doubtful. The 
transfer of Cryptochilus, Calanthe and Oreorchis to Vandeae was forced upon us by 
the fact that the gland terminating the caudicle is, in all three, unmistakeably derived 
from the stigma. For this reason we have also restored to Vandeae the genus Jone 
which had been merged in Bulbophyllum,—a genus to which it has undoubtedly а 
great resemblance in its vegetative organs. 
It only remains to say a few words in explanation of the re-arrangement of 
the genera formerly referred to Neottiee. We found that these genera may, as we 
believe, be arranged in two groups by following the characters afforded by the pollen. 
In one group the pollen is powdery (very rarely granular); in the other it is 
always granular or sectile. The plants with powdery pollen have a terminal anther, 
and their pollinia cohere by their sides, but they have neither caudicles nor glands. 
These we have formed into a tribe under the name Listereae. The genera with 
granular or sectile pollen have a posticous anther, and the pollinia are attached to a 
single gland by either one or two caudicles. These we have formed into our tribe 
Goodyereae. The location in Listereae of Epipactis and Cephalanthera appears rather 
anomalous; and there is no doubt that, in their vegetative organs, they resemble 
no other genus in the group; but their pollen is unmistakably powdery. 
Our study of the Sikkim species convinces us that the fertilization of orchids by 
insect agency is by no means so universal as is sometimes supposed. We have found 
