OF THE INTERIOR OF WESTERN AUSTRALIA. 255 
the pollen out of the anthers and give it a chance of reaching 
its destination. A shrub and a tree might thus be enabled to 
slowly extend its area if the necessary crossing were effected by 
very rare visits from insects; and this at most is, I think, all that 
can obtain in the desert, at least in places removed from a per- 
manent supply of water. Coleoptera, it may be added, are more 
abundant in the desert than are other insects, nearly 200 having 
been secured by the Elder Expedition *; but I doubt whether 
many of these insects visit flowers—at least, except for the case 
at Gnarlbine already mentioned, I do not remember to have seen 
one upon a flower. 
The comparative abundance of Loranthacew in the desert has 
been already mentioned; one has not to go far in search of a 
cause for this. ‘These parasites obtain all the water they need 
from their hosts, and, provided that the latter can maintain their 
existence, the parasite is safe. The seeds are probably diffused 
by the few frugivorous birds that haunt the desert solitudes. In 
Brazil I was struck by the extent of the ravages inflicted by 
these parasites upon their hosts. I saw no signs of such destruc- 
tion in Australia: indeed, their usually small and leathery or 
woolly leaves are evidently adapted to keep down transpiration, 
and thus to reduce to a minimum the injury they inflict upon the 
plants which support them. 
It has already been mentioned that in the desert shrubs and 
trees predominate over herbs; indeed, no less than 538 of the 
819 indigenous species have one or the other habit. Moreover, 
a considerable proportion of the 311 herbs are perennials pro- 
vided with woody rootstalks, so as in their habit to approach 
undershrubs. Annuals enjoy but a precarious existence during 
the cool weather of early spring; probably some years are 
more favourable to them thau others, at least Iinfer this from 
their greater abundance during the first spring I was in the 
country. 
XEROPIILY. 
Adaptation to drought is shown in many ways by the plants of 
the West Australian desert, and I propose here briefly to reca- 
* Many of these, however, came from South Australia, The fauna as a 
whole may be described as mainly Lacertilian and Coleopterous (vide Elder 
Expedition Report). 
