VALPARAISO. 545 



It has a most strange appearance. Other forms of Cacti, each 

 adapted to the climate of a particular altitude, succeed one 

 another as the slope of the Andes is climbed ; those that lie 

 highest being dwarf forms scarcely rising above the ground. 



On the Cereus Quisco grows a Mistletoe (Loranthus aphijllus). 

 This Mistletoe is most remarkable, because, like the plant on 

 which it is parasitic, it is entirely devoid of leaves. It is 

 extremely abundant, growing on nearly all the Cereus trees, and 

 is very conspicuous, because its short stems are of a bright pink 

 colour. I could not understand what it was at first, as it looked 

 like a pink inflorescence of some kind belonging to the Cactus. 



Mr. Thiselton Dyer 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 para- 

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

 the Cactus, which curiously simulates a mass of mycelium, 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, so that from that reason they 

 were difficult sometimes to find. He pointed out to me examples. 

 The leaves of one Australian species of Mistletoe, Loranthus 

 celastroicles, which grows on species of Eucalyptus, are so like 

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

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

 Australian species of Loranthus have commonly two very 

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

 L. celastroicles the broad-leaved varieties grow on Banksias mostly, 

 and the narrow-leaved on Eucalypti ; but both forms occur on 

 species of Casuarina, which is a tree with narrow needle-like 

 leaves ; all gradations occur between the two varieties of this 

 Mistletoe.* 



* " Flora Australiensis," Vol. Ill, pp. 388, 390. Bentham and Mtiller. 



London, 1866. 



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