. The fungi which cause plant disease . Plant diseases; Fungi. ASCOMYCETES (p. 64) 2, 7, 19, 25, 46, S2, 53, 62 The distinguishing mark of this group is the ascus. This in its typical form is shown in Fig. 73, as a long, slender or club-shaped sac in which the spores are borne. The number of spores in the ascus is usually definite and is commonly of the series, 1, 2, 4, 8, 16, 32, 64, etc., the most common number being 8. The spores vary in size, color, shape, markings and septation. The asci in most genera are arranged in a definite group, a layer, con- stituting the hymenium which may be eit
. The fungi which cause plant disease . Plant diseases; Fungi. ASCOMYCETES (p. 64) 2, 7, 19, 25, 46, S2, 53, 62 The distinguishing mark of this group is the ascus. This in its typical form is shown in Fig. 73, as a long, slender or club-shaped sac in which the spores are borne. The number of spores in the ascus is usually definite and is commonly of the series, 1, 2, 4, 8, 16, 32, 64, etc., the most common number being 8. The spores vary in size, color, shape, markings and septation. The asci in most genera are arranged in a definite group, a layer, con- stituting the hymenium which may be either concave, convex, or flat. Between the asci in the hymenium are often found slender hyphal threads of various form, the paraphyses, Fig. 73. The hymenium may be borne in or upon a firm substratum of woven threads, the stroma, or upon a very tenuous substratum, the subicu- lum, or without any definite subascal structure. The stromata vary widely in character, size, tex- ture, color, surface, form, etc. The mycelium is usually abundant, branched and septate, the septation readily distinguishing this group from the Phycomycetes. In many species the mycelium weaves together into a false parenchyma and constitutes relatively large -p^^ 73. —Portion spore-bearing structures. Fig. 74. "L^ing'ScTa'iS The ascigerous organ, ascocarp, or ascoma, paraphyses. Af- , , , . ii. • ter Chamberlain. if saucer-shaped and open is an apotbecium, Fig. 92; if closed a perithecium, Fig. 144. In other cases, the ascigerous layer covers the exterior surface. Fig. 74. On the boundary lines between the Ascomycetes and other groups are fungi which do not present the typical Ascomycete picture but which are regarded as probably belonging to the group, i. e., transition forms between this and other groups. Among such are 113. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfungi, bookyear1913
