. Chestnut blight. Chestnut blight; Chestnut. Endothia Canker of Chestnut SS9 They are closely crowded together, so that in cross section they appear to make up a pseudoparenchymatous tissue. These cells are more densely filled with protoplasm, and contain more pigment, than the interior cells. Pycnidia On smooth-bark, young cankers, especially in the summer, the outer cork layer is raised in numerous little blisters, with slender, yellow, waxy tendrils curling from their ruptured apices (Plate XXXVIII, Fig. i). Under each blister is a single somewhat globose pycnidiimi, surrounded by a scanty
. Chestnut blight. Chestnut blight; Chestnut. Endothia Canker of Chestnut SS9 They are closely crowded together, so that in cross section they appear to make up a pseudoparenchymatous tissue. These cells are more densely filled with protoplasm, and contain more pigment, than the interior cells. Pycnidia On smooth-bark, young cankers, especially in the summer, the outer cork layer is raised in numerous little blisters, with slender, yellow, waxy tendrils curling from their ruptured apices (Plate XXXVIII, Fig. i). Under each blister is a single somewhat globose pycnidiimi, surrounded by a scanty, loose growth of white or slightly yellowish mycelium. There is as yet no definite stroma. The wall of the pycnidium is composed of closely tangled hyphse; that is, it is not a definite pseudoparenchymatous wall. The cavity may be a fourth of a millimeter in diameter and is almost round in cross section at first, becoming irregular only with age. The conidiophores form a dense, brush-like fringe and extend directly out into the cavity from every point of the wall (Fig. 86). They are of uneven lengths, the majority being 20 to 40 n long, and are about /* in diameter. They may be simple or branched. Spores are cut off successively from the conidiophores or their branches and soon fill the cavity, but, since the production of spores does not cease when the cavity is filled, they are forced out through an irregular ostiole at the top in yellow tendrils. These tendrils take on a reddish tinge as they become old. They vary in thickness from the diameter of a hair to half a millimeter, and in length from a mUlimeter to three or four centi- meters. They occur singly and are usually spirally twisted into one or more coils (Plate XXXVIII, Fig. i). The older pycnidia contained in mature stromata differ from these in some respects. The cavity is convoluted or labyrinthiform, and irregular (Fig. 84, and Plate XL, Fig. i). When cross sections of these stromata are cut, a single section
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