. Diseases of plants induced by cryptogamuc parasites; introduction to the study of pathogenic fungi, slime-fungi, bacteria, and algae. English ed. by William G. Smith. Plant diseases; Parasitic plants. POLYI'OKUS. 440 but later becmnes brown, aiitl, on IteiiiL; tcjuchud, tlt'fi) red. The spores are white, and various forms of hairs occur anionic the basidia. Young sporophores appear as little brown cushions mi felled timber, also on living stems of pine, and, according to Magnus, on Weymouth pine. The disease generally makes its first appearance in roots and lower parts of the stem, spreading
. Diseases of plants induced by cryptogamuc parasites; introduction to the study of pathogenic fungi, slime-fungi, bacteria, and algae. English ed. by William G. Smith. Plant diseases; Parasitic plants. POLYI'OKUS. 440 but later becmnes brown, aiitl, on IteiiiL; tcjuchud, tlt'fi) red. The spores are white, and various forms of hairs occur anionic the basidia. Young sporophores appear as little brown cushions mi felled timber, also on living stems of pine, and, according to Magnus, on Weymouth pine. The disease generally makes its first appearance in roots and lower parts of the stem, spreading thence into higher parts. Diseased wood has a characteristic odour of turpentine: it has a cohnir, and, as destruction proceeds, it gradually shrinks and disintegrates till it liecomes so soft as to be easily powdered between the fingers. Where broken over, the wood is often covered with a thin white coating of mycelium incrusted in resin so as to appear like chalk. The mycelium penetrates the cell-walls in all directions. A very characteristic feature of this parasite is furnished by shrinkage-fissures in the thick walls of the tracheids of the summer-wood (Fig. 280). These are numerous and run ujjwards from right to left extending through' the whole wall to the outermost layers. They differ from the fissures in tracheids destroyed by P. , in that they run round the whole circumference of the cell, instead of being small and set vertically above each othei'. Polyporus (Fomes) pinicola (Sw.) ( Ameri(;i). Spiiruphores thick, hoof-like or liracket-shaped, with a smootli dark-grey up])er side and a bright red rounded margin. Tiie hymenial layer is smooth and yi-lldwisii, tlie spore-powder white. In section the are white. Tlie species is fn'([uent nn living stems nl' sjiruce, pine, and lir, aNo on hir'-li mid cliciTy. Polyporus iFomes) marginatus Ki. (I .s. AnuTica). Spom- ph'jres with red margins, and otherwise very like those of the pr
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectparasit, bookyear1897
