Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . ers already mentioned. After it has grown for awhilein this way it sends up certain vertical branches (b),which soon develop transverse partitions, and thus pro-duce the small oval summer spores. These are lightand easily distributed by the wind, and serve for therapid extension and propagation of the fungus duringsummer. Later in the season the mycelium produces anotherkind of spores—the so-called winter spores. These aremore complicated in structure than
Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . ers already mentioned. After it has grown for awhilein this way it sends up certain vertical branches (b),which soon develop transverse partitions, and thus pro-duce the small oval summer spores. These are lightand easily distributed by the wind, and serve for therapid extension and propagation of the fungus duringsummer. Later in the season the mycelium produces anotherkind of spores—the so-called winter spores. These aremore complicated in structure than their summer repre-sentatives ; as seen under the microscope, they consist 86 PUKGI AXD FUi^GICIDES externally of a small spherical case, from which projectfifteen or twenty, or sometimes more, rather long deli-cate ajipendages with recurved tij^s, as seen in a, Fig. is the outer spore-case (which hotanists call the2JerUliecium). If it be crushed it will break open onone side, and there will be pushed out about half adozen small, OTal, flattened bodies—the inner sporecases, or asci—within which may be seen from four to. FIG. 42. POWDEKY MILDEW. 5L\, Peritliecium; 6, mycelium; c, germinating spore. six small bodies, which are the winter spores. Bymeans of these the fungus passes through the winter. Microscopic Characters.—A good idea of thestructure of this powdery mildew may be obtained fromFig. 42. A small piece of the mycelium running overthe surface of the leaf is represented in l; on the lowerside are tAvo of the i^eculiar suckers which penetrate thetissues of the host-i^lant to draw out nourishment forthe fungus, and on the upper side are represented thevertical branches from which the summer spores are pro-duced, as well as one loose spore. In c one of these iHE GKAPE a:n^thracnose 87 spores is shown in process of germination, one of thegerm tnbes having already formed a sucker on its winter spore case, with the inner cases escapingthrou
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectpathoge, bookyear1896
