PARASITE PLANTS. 
Soon after leaving Sta. Rosa the hill- sides are seen 
to be covered with the tall candelabra-like Cactus, 
Cereus Quisco. It has a most strange appearance. 
Other forms of Cacti, each adapted to the climate of 
a particular altitude, succeed one another as the 
slopes of the Andes are climbed, those that lie highest 
being dwarf forms, scarcely rising above the ground. 
On the Cereus Quisco grows a Mistleto ( Loranthus 
aphyllus) . This Mistleto is most remarkable, be- 
cause, , "Ilke 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 
Mistleto, which draws the nourishment from the in- 
terior 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 mycelium, such as pro- 
duced by 1 a parasitic fungus. The fact that the 
Mistleto 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 Mistleto grow- 
ing on the various species of Gum trees (Eucalyptus) 
simulated in their foliage that of the tree on which 
they grew, solhat from that reason they were difficult 
to find. He pointed out to me examples. The 
leaves of one Australian species of Mistleto (Loran- 
thus celastroides), which grows on a species of Euca- 
lyptus, are so like those of the Eucalyptus itself that 
the varieties of the species have been termed L. 
eucalyptifolius. The Australian species of Loranthus 
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 
occur on a species of Casuarina, which is a tree with 
narrow needle-like leaves ; all gradations occur be- 
tween the two varieties of this Mistleto. * Loranthus 
aphyllus is the only Loranthus without leaves. It 
grows only upon the Cereus Quisco. There ar& how- 
ever, species of the genus Misodendron / of the 
: Mistleto family which are leafless, and yet /grow on 
trees with well developed leaves, as the Fuegian 
Beech trees, Probably the leafless Mistleto on the 
Cactus has got rid of its leaves for the same reason as 
the Cactus, viz., to minimise loss of moisture by evapo- 
ration in an arid climate — the Australian Mistletos 
Y possibly for adapting their leaves to the forms of those 
i of the Gum trees in order to benefit the trees, and 
e thus themselves, by interfering as little as possible 
with the vegetation at the roots of their host. They 
ff can hardly be supposed to gain by being incon- 
e ^picuous, but must rather be certain to lose thereby. 
Notes of a Naturalist on the “ Challenger ,” by H. N 
11 Moseley. • 
0 1 2 345678910 Missouri 
Botanical 
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