474 CHILE. 



looked like a pink inflorescence of some kind belonging to the 

 Cactus. 



Mr. Thiselton Uyer has examined the mass of parasitic tissue 

 of this Mistletoe, which draws the nourishment from the interior 

 of the stem of the Cactus. He finds that, having a soft and 

 succulent matter in which to ramify, the basal fibres of the 

 parasite form a large spongy mass of great size within the stem 

 of the Cactus, which curiously simulates a mass of myceliuw, 

 such as produced by a parasitic fungus. 



The fact that the Mistletoe growing on a leafless Cactus has 

 no leaves itself, reminded me of a remark which Sir William 

 MacArthur made to me in New South Wales. He told me 

 that he had noticed that the Mistletoes growing on the various 

 species of Gum-trees {Eucalyptus) simulated in their foliage 

 that of the tree on which they grew to such an extent that 

 they were often difficult to find. He pointed out to me 

 examples. 



The leaves of one Australian species of Mistletoe, Lorauthus 

 ce/asfroides, which grows on species of Eucalyptus, are so like 

 those of the Eucalyptus itself, that the varieties of the species 

 have been termed L. eucalyptoides and L. eucalyptifolius. The 

 Australian species of Lorajtthus have commonly two very 

 different forms of leaves, broad and narrow. In the case of 

 L. celastroides the broad-leaved varieties grow on Banksias 

 mostly, and the narrow-leaved on Eucalypti; but both forms 

 are found on species of Casuarina, which is a tree with narrow 

 needle-like leaves ; all gradations occur between the two 

 varieties of this Mistletoe.* 



Loranthus aphyllus is the only Loranthus without leaves. 

 It grows only upon the Cereus quisco. There are, however, 

 species of the genus Misodendron of the Mistletoe family, which 

 are leafless, and yet grow on trees with well-developed leaves, 

 such as the Fuegian Beech Trees. 



Probably the leafless Mistletoe on the Cactus has got rid of 

 its leaves for the same reason as the Cactus, viz., to minimise 

 loss of moisture by evaporation in an arid climate. The 

 Australian Mistletoes possibly are adapting their leaves to the 

 forms of those of the Gum-trees, in order to benefit the trees, 

 and thus themselves, by interfering as little as possible with the 

 vegetation at the roots of their host. They can hardly be 

 supposed to gain by being inconspicuous, but must rather be 

 certain to lose thereby. 



After accompanying me for about half the distance up the 

 Pass, my companion, Lieut. G. R. Bethell, had to return, and 



* "Flora Australiensis," Vol. III., pp. 38S, 390. Bentham and Miiller. 

 London, 1866, 



