308 MR. W. B. HEMSLEY ON SOME 
prey upon the same kinds of plants, both being common on the 
“ mingi-mingi,” Cyathodes acerosa, R. Br., one of the small rigid- 
leaved Epacridee. But a much more remarkable instance of 
double parasitism is offered by the genus Phacellaria. This is a 
genus of leafless parasites belonging to the Santalacez ; and all the 
specimens in the Kew Herbarium of the three or four species 
known are parasitic on various leafy species of Loranthus. I de- 
scribed a species discovered in Burma by Sir Henry Collett, in our 
Journal (vol. xxviii. p. 122, pl. xvii.). The specimen is not actually 
attached to the host-plant; but Sir Henry noted in the field that 
such wasthecase. I have shown you examples of leafy parasites 
growing on other leafy parasites, and also of leafless parasites 
growing on leafy parasites; but I have not met with any instance 
of two leafless parasites being associated in the same manner. The 
principal genera of Loranthacee—Loranthus, Viscum, Phoraden- 
dron, Arceuthobium—have both leafy and leafless species; and it 
frequently happens that the leaves of the leafy species are so like 
those of the host-plant, that, like Tupeia, they are indistinguish- 
able except on very close examination. The common Mistletoe, 
which grows on such a great variety of trees and shrubs, presents, 
so far as I know, no striking similarity in foliage to any one of its 
hosts. On the other hand, one of the commonest Australian 
species of Loranthus (L. pendulus, Sieber) mimics, if I may use 
the term, the foliage of more than one of the plants upon which 
it preys so closely that branchlets of host and parasite might pass 
for the same. The specimen of a variety of Loranthus pendulus 
side by side with one of its host-plants, Eucalyptus amygdalina, 
Labill., is a striking instance; and every one will agree that when 
not in flower it might escape the notice of the most acute observer. 
The essential difference is, that the pərasite has opposite leaves 
and the host alternate leaves. Another of the host-plants of 
Loranthus pendulus is Fusanus spicatus, R. Br., a member of 
the Santalaceæ. This has opposite leaves; and is otherwise so 
like the parasite that, with the specimens before you, it is suff- 
cient to point out the fact. Whether these resemblances are due 
to association or to local climatal conditions favourable to the 
development of the same type of foliage, I am not prepared to 
say. Itis equally impossible for me to judge whether the parasite 
derives any benefit or protection from the resemblance. Rather 
than speculate on the subject, I prefer leaving its elucidation to 
those who have opportunities of studying the conditions and rela- 
tionships of the plants in the living state. Some of the parasites 
