Page:A primer of forestry, with illustrations of the principal forest trees of Western Australia.djvu/105

99 growing on the flats lying between the hills and the coast. It is a parasite, like the sandalwood. This fact was established recently by Mr. D. A. Herbert, B.Sc, Government Botanist and Plant Pathologist, who, after careful investigation, found that the Christmas Tree from its roots throws out shoots underground, which may travel considerable distances before they meet the roots of a "host." but having done so, they attach themselves to the roots of this host and draw nourishment from them. The curious thing about the parasitism of the Christmas Tree is its wide range of hosts. Trees and shrubs of various species have been found bearing the suckers of the Christmas Tree, also grasses and even the common carrot.

Mistletoe.—The Mistletoe is a very common object in the forests of the world. It is found all over Europe, in Asia, including Japan, in America, and in Australia. There are a great many groups or genera of Mistletoe and each genus has a scientific name which distinguishes it from the others. The European genus species is named Viscum, and the Australian genus Loranthus, of which there are a number of species in the States of the Commonwealth. Mistletoe does not spring from the ground like most other plants. It has roots, however, which are embedded in the bark or wood of trees, and from these trees the Mistletoe draws its nourishment. Mistletoe is a parasitic growth and the tree on which it feeds is called its "host." Mistletoe is found attaching itself to many kinds of trees and does not seem to have any marked preference for a particular kind. It may be said generally that it is found much more frequently on rough-barked trees than on those with smooth barks. The mistletoe is distributed by those birds that feed upon its berries, the hard seeds pass through the birds' alimentary canal and are deposited on the branches of other trees: thus the Mistletoe gets distributed all over the forest. The seeds, which germinate in Spring, first of all develop a kind of sucker from whose centre a fine root appears, which pierces the tissues of the bark. This main root penetrates to the wood of the branch or stem, which it is too delicate to enter. It, however, holds its position and the end becomes covered when the branch or stem forms new wood. As time passes the root seems to have gone deeper into the wood, but in reality it is the growing thickness of the wood that gives the appearance of penetration. In time the parasite becomes firmly attached to it "host," and secures the nourishment it requires. The effect of Mistletoe on forest trees is to reduce their vitality and to decrease the production of flowers and fruit. Mistletoe, however attractive it may be in itself, and however picturesque the appearance it imparts to woodland scenery, must be regarded as an enemy of the forests.