. Diseases of deciduous forest trees. Trees -- Diseases and pests. 54 DISEASES OF DECIDUOUS FOREST TREES. surface of the timber upon which they happen to be growing. They form readily in a moist atmosphere. They first appear as tiny masses of mycehum, which grow out usually from the medullary rays, and generally several within a small area. These small masses rapidly grow larger, until in the course of a few days they have united in a single mass visible to the naked eye. After they reach the size of one-eighth inch in diameter, or thereabouts, the hymenial layer begins forming on the lower su
. Diseases of deciduous forest trees. Trees -- Diseases and pests. 54 DISEASES OF DECIDUOUS FOREST TREES. surface of the timber upon which they happen to be growing. They form readily in a moist atmosphere. They first appear as tiny masses of mycehum, which grow out usually from the medullary rays, and generally several within a small area. These small masses rapidly grow larger, until in the course of a few days they have united in a single mass visible to the naked eye. After they reach the size of one-eighth inch in diameter, or thereabouts, the hymenial layer begins forming on the lower surface of the knob. A mature fruiting body may be formed in about a week where the fungus is in a condition for rapid development. The young sporophoros seem at first to grow perpendicularly from the surface from which they protrude, irrespective of whether this be a horizontal or a vertical surface. Very soon after their appearance, however, the shelves assume a horizontal posi- tion. Where wood is placed in con- tact with the ground, the sporo- phores are fre- quently cramped and crowded by soil or stones, and in such cases the growing myce- lium adapts itself to the available space and pro- duces sporo- FiG. 6.âAn oak railroad tie with fruiting bodies of Poi2/«<i<'tt«''er«''(o.'or. â p.' nf (^^^t^T- r conceivable shape and size. It is not at all uncommon to find large masses of the sporophores forming in the upper surfaces of cinder ballast on railroad tracks. The mycelium in this case binds the individual cinders together, forming great clumps 6 or 8 inches in diameter. AMiere two or more sporophores start on a surface in close proximity they will as a rule fuse l)cfore reaching maturity, and as a result of this fusion long sheets may form composed of two or many sporophores which have grown together laterally (fig. 6). Polystictus versicolor usually starts its development in some season check, although it may start to develop on the surface of a sti
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