Too THE ORCHID REVIEW. APRIL, 1908 
reduction, there being no leaves and no green colouring matter, but simply a 
mass of branching coral-like roots. The plant is a saphrophyte, living on 
decaying vegetable matter, having lost the power of deriving it direct from 
the soil. 
Vanilla planifolia (next shown) closely resembles Pogonia in the condition 
and consistency of the pollen, but the rostellum is enlarged, becoming a 
large flap-shaped body, which hangs over the stigma, and moves on a kind 
of hinge at the base. The lip is united to the margins of the column for a 
considerable distance, forming a broad tube, and down this the bee which 
fertilises the flower has to crawl. On the disc of the lip is situated a curious 
tuft of hairs or lamelle, directed backwards, which retard the insect’s 
retreat, and on lifting itself over them, it lifts the flap-like rostellum, and if 
it has pollen on its back it must inevitably leave it upon the stigma. The 
Vanilla is almost the only Orchid of much economic importance, and its 
culture now forms a great industry, but owing to the absence of the 
necessary bee from most of the localities where the plant is cultivated the 
flowers have to be fertilised by hand. In Mexico and Central America, 
however, where the plant and bee are both indigenous, this is not necessary. 
The Vanilla is atall climber, a modification of the vegetative organs 
adapting it to-its natural conditions of living in a tropical forest, growing in 
the soil of the forest floor, and sending up its branches into the trees, SO 
that the flowers and fruit may develop in the light and sunshine. 
The preceding are representatives of a very large and diversified group of 
terrestrial Orchids, the Neottiez, which is not represented in cultivation in 
proportion to its numbers, because many of the species are not showy. 
They exhibit great diversity among themselves, and in the large Australasian 
subtribe Diurideze occur many very highly complex structures, of which the 
genus Pterostylis is one of the most remarkable, having a sensitive lip, 
which closes up and partially imprisons its insect visitors. 
The Ophrydez follow naturally, as another very large and widely 
diffused tribe of terrestrial Orchids, which is familiar to us through the 
genera Orchis, Ophrys, and Habenaria, also by such cultivated types 4§ 
Disa, Cynorchis, and others. In habit a good many of them resemble the 
Neottiez, but in the structure of the anther and arrangements for fertilisa- 
tion they are much more highly specialised. There is not time to go into 
much detail respecting them, but a slide of Bonatea antennifera illustrates 
one of the most highly complex of existing Orchids. 
The first thing which strikes one on seeing this flower is the large 
number of parts, and there is a difficulty in making out what some of them 
are. The lip is divided into three narrow lobes, but what appear to be tw? 
additional lobes prove to belong to the petals. These latter are divided t? 
the base into two diverging lobes, the upper half of each being appressed to 
