Page:The Oak.djvu/179

Rh fungus are able to infect oak planks, beams, etc.; and the mycelium rapidly spreads on and in the wood, destroying the cell-walls, and causing the wood to shrink and crack and warp, and finally to fall to pieces. Thorough ventilation is fatal to the fungus and stops the rot.



A series of enemies to the oak-tree not yet referred to are various gall-insects, so called because they pierce the young leaves or buds, etc., and lay their eggs in the wound; the irritation set up suffices to induce a flow of food materials to the stimulated spot, and the overfed