AvuGuST, 1912.] THE ORCHID REVIEW. 227 
({tetrads), owing to the fact that at the last division of the pollen cells 
complete separation of cells does not take place, and this represents the 
first stage of their union into pollinia. This powdery pollen is characteristic 
of the early genera of the tribe Neottiez, but soon we find a further develop- 
ment, in the union of the compound grains (tetrads) into little packets, 
each united to a central axis by a short stalk—composed of modified pollen 
grains—forming the sectile type of pollinia. Correllated with this develop- 
ment we find the viscus secreted by the rostellum hardened into a little 
gland, to which the sectile club-shaped pollinia are attached. The gland 
still remains sticky at its extremity, and thus adheres to the body of the 
visiting insect, and is carried away bodily. 
Among the higher types of Neottiez we find further. development of the 
rostellum, to prevent the pollinia from falling on to the stigma of the same 
flower, as in Vanilla, of various special developments of the lip and column, 
as in the Diuridez, and such complex modifications as the sensitive lip of 
Pterostylis,and others previously mentioned, all of which are adaptations 
to secure cross-fertilisation by particular insects, and to exclude other 
insects which would plunder the flowers without effecting the desired end. 
We also find many other modifications of floral structure, all directed to 
the same purpose. 
Corresponding vegetative developments among the Neottiez are found, 
but are far less numerous than those seen in the epiphytic section of the 
Order. The plants are still terrestrial, and the great majority of them of 
the general type seen in the well-known genus Spiranthes. We find, how- 
ever, modifications in the fleshy roots of the Spiranthes group; the more 
or less tuberiferous development of the rhizome of Diuridez; the climbing 
stems of Vanilla, which often ascend to the tops of the tallest trees; in the 
fleshy leaves of the last-named genus; in the handsomely variegated leaves 
of Ancectochilus and a few other genera, the functions of which are 
obscure; and in the suppression of the leaves in one section of Vanilla, the 
function of nutrition being carried on by the chlorophyll in the stems. 
We have also the remarkable development of a leafless saprophytic habit, as 
in Neottia, Epipogon, Galeola, and a few others which grow upon decaying 
vegetable matter. 
Modifications in other characters could be pointed out, as the fleshy 
fruits and rounded crustaceous seeds of Vanilla, and the broadly winged 
seeds of Galeola, all of which are adaptations to particular methods of 
existence. The Neottiez generally inhabit moist and shady situations, and 
are most abundant in warm regions, becoming much less numerous in 
temperate climates. 
Another stage of development is seen in the Ophrydex, which much 
resemble the Neottiez in habit, while the structure of the pollinia is very 
