Page:The Oak.djvu/174

156 paucity of water at those parts, the parasite taking much of that which reaches the injured place, and the impoverished wood allowing less to pass than it would normally have done.

Among the fungi there are several enemies to the oak-tree. The leaves are attacked by Phyllactinia, one



41.—Loranthus europœus. A. Lower part of stem attached to branch of oak, both denuded of cortex. B. Longitudinal section through one of the haustorial strands, showing its progress year by year, as the branch thickens. C. Transverse section, through a branch which has long been badly infested with the Loranthus; a a, dead remains of old haustorial strands; b b, young Loranthus plants developed as buds from the older ones. The asterisks mark still younger specimens. (Hartig.)

of the mildews, which forms white networks, like spiders' webs, on their surfaces. Numerous small ascomycetous fungi are found on the dying and dead leaves, but these do not directly injure the living tree.

Other fungi are found in the cortex, and one of the most interesting of these is a red Nectria, the spores of