CROSS-POLLINATION. 59 
at the same time, m which case the flower can pollinate itself. But 
in a considerable number of instances self-pollination is impossible, 
and the pollen of one flower must be applied to the stigma of 
another. Such cross-pollination, as it is called, has been proved 
to be beneficial for many plants. A large percentage of New Zea- 
land trees and shrubs have the pollen-bearing flower on one plant 
and the ovule-bearing flower on another. Others, again, are so con- 
structed that the pollen is ripe before the stigma of the same flower 
is ready to receive it, or the stigma may in other species be developed 
before the pollen. In all these cases cross-pollination is alone pos- 
sible. This may take place in two ways: either the wind may 
carry the pollen—light as dust—from one flower to another, as in 
the genus Coprosma and in many other cases, or animals may convey 
it dusted on some part of their bodies. In accomplishing this work, 
insects play a very important role. Birds also pollinate a few New 
Zealand plants, amongst others the puriri (Vitex lucens), the waiu-atua 
(Rhabdothamnus Solandri), and the New Zealand flax (Phormium 
tenax)—this latter not a forest-plant. 
The story of how New Zealand plants are pollinated yet remains 
to be told by the plants. Certainly in a calm forest-interior the 
wind can have but little effect, yet the coprosmas—so abundant— 
are apparently suited for wind-pollination alone. Nor are there 
many showy flowers, as already seen, which could on that account 
attract insects. On the other hand, there is abundant honey in 
some species, and usually plenty of pollen, both of which many insects 
love, and it may be that honey or pollen alone, without brilliant 
coloration to guide the insect visitors, is a sufficient attraction. 
There are many distinct forest-associations in New Zealand. 
Here the most important—the kauri, the mixed taxad, the kahika- 
tea, and the southern-beech groups of associations—are dealt with in 
quite a general manner 
The kauri forest extends from the north of the North Auckland 
Botanical District to almost latitude 38°. It is probably the noblest 
tree-community of the temperate zone. The kauri (Agathis australis) 
is not a close relation of the Old World pines, but is nearer to trees 
of the mofikey-puzzle (Araucaria) family. 
A kauri forest by no means consists of that tree alone, for the 
taraire (Beilschnuedia taraire)—very handsome, with its rather large 
leaves, darkish-green above and bluish- white beneath—is often 
