Page:A primer of forestry, with illustrations of the principal forest trees of Western Australia.djvu/100

94 CHAPTER XI.

SOME CURIOUS FOREST PLANTS.

The forested regions of Western Australia contain a number of strange growths to which it is rather difficult to apply the term "tree," if the word is to carry its popular meaning. These growths sometimes have branches, but they are quite unlike the branches of ordinary trees; their outer covering cannot correctly be described as bark, and their trunks yield no timber. The most prominent, as well as the most common, of these odd-looking members of the forest community are the "blackboy" (Xanthorrhoea Preissii), the "grass-tree" (Kingia Australis), and the "Zamia" palm (Macrozamia Fraseri). It is certain, according to the evidence adduced by botanists and geologists who have studied the subject, that the three plants named nourished in Western Australia, long before it contained the eucalypt trees, as we know them now. How they managed to survive through the long ages of forest development from lower to higher forms, and whether they are precisely the same in size, formation, and qualities as they were in that far-back past, are questions we cannot answer to-day with absolute certainty. All we can assert with confidence is that the black-boy, the grass-tree, and the zamia grew in Western Australia before the eucalypts had reached the stage at which we now find them.

Blackboy.—This plant is a familiar object in the South-Western portions of the State, and once seen is always remembered. The majority of those met with in the bush average about seven to eight feet in height, but they may be met with of all heights up to 15 feet. The bole or barrel may range in diameter from five or six inches up to about a foot. The outside portion of the bole is composed of layers of hardened masses of the persistent bases of old leaves. This outer layer is heavily impregnated with a gum or resin which is highly inflammable; when fire sweeps through the bush, the blackboy is readily attacked, with the result that the trunks of these trees are always found in a blackened condition. The central core is of fibrous material which is sometimes of a hardness that would almost permit of its being termed "wood." From this core under proper treatment sugar may be obtained, as well as a number of chemicals of commercial value. The gum or resin of blackboy is used for several trade purposes, but mainly in the manufacture of varnish. In some parts of South Australia blackboy grows freely, and is there known as yacca or "grass-tree." The South Australian variety is very similar to that of Western Australia.

Grass-tree.—The grass-tree is not quite so common in the West Australian forests as the blackboy, but it is quite as distinctive. Botanists class it as well as the blackboy in the lily family. It is found only in Western Australia. In appearance it is very like blackboy, but the properties of the two trees and their commercial possibilities are quite dissimilar. The grass-tree may be readily distinguished from the blackboy by the flowering stalk. In the grass-tree the flowers and seeds are borne on short stalks about a foot long, many of which stand out from the centre of every plant like drum sticks. The blackboy, on the other hand, has one long flowering stalk only, of quite a different type, arising from each mass of leaves. Like the blackboy it is found scattered over a considerable portion of the South-West, especially between the Darling Range and the sea, and in the karri country. It reaches a height of from 6 to 25 feet, and the bole has an average