. Chestnut blight. Chestnut blight; Chestnut. Endothia Canker of Chestnut S6i- are not typically curved is an additional reason why this stage should not be referred to Cytospora. The spore membrane is thin and smooth. The spores are filled with dense homogeneous protoplasm, and each spore contains a single smaU, elongated nucleus near the center. There is also a polar body in each end. Perithecia The mature stromata on older cankers have numerous projecting papilla on the surface (Plate XXXVIII, Fig. 2). The black speck at the tip of each papilla is the opening of a perithecium, the body of w
. Chestnut blight. Chestnut blight; Chestnut. Endothia Canker of Chestnut S6i- are not typically curved is an additional reason why this stage should not be referred to Cytospora. The spore membrane is thin and smooth. The spores are filled with dense homogeneous protoplasm, and each spore contains a single smaU, elongated nucleus near the center. There is also a polar body in each end. Perithecia The mature stromata on older cankers have numerous projecting papilla on the surface (Plate XXXVIII, Fig. 2). The black speck at the tip of each papilla is the opening of a perithecium, the body of which is located down in the bottom of the stroma and is connected with the apex by a long, black neck. These papiUas may scarcely project above the surface of the stroma, or, on the other hand, they may be a. Fig. 88.— Stages in the development of the perithecium a, Cross section at the stage when the cavity is occupied by young paraphyses. The neck is not shown b, Tip of the neck in cross section as it appears, pushing up through the stroma at the same stage as shown in (a) ... c, Lower part of neck and canal when the perithecium is almost mature, showing periphyses projecting into the canal millimeter or more in length. They are longer in moist, shaded places than in dry, lighter surroimdings. There are commonly fifteen to thirty perithecia in a stroma, but the number varies greatly, over forty having been counted in some cases. In Fig. 85 (page ss8) and in Plate XL, Figs. 2 and 3, perithecia in longisection are shown. As seen tmder the hand lens the wall of the body of a perithecium is gray or lead-colored, while the neck is jet black and shining like anthracite. The mature perithecia measure about 350 to 400 n in diameter and are mostly spherical, but the shape is often modified by pressure of surrounding perithecia. Since the perithecia are always in the bottom of the stroma next to the host tissue, the length of the neck varies with the luxuriance of the stroma and the
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Keywords: ., bookcollectionbiodiversity, bookleafn, booksubjectchestnutblight
