. Comparative morphology of Fungi. Fungi. Fig. 372.—Types of aecia. 1. Caeoma of Phragmidium Rubi. P, paraphyses. 2. Aecidium of Uromyces Erythronii. Per, peridium. (1 X 400; 2 X 300; after Sappin- Trouffy, 1896.) lum Sempervivi and Puccinia obtegens (P. suaveolens), they have a sweetish odor, in Gymnoconia Rosae, an offensive odor. Their further develop- ment is unknown. In some species, , Phragmidium violaceum, they appear to degenerate early (Blackman, 1904); in others, as Cronartium ribicola, they appear to be normal (Colley, 1918). In any case, they seldom germinate and when they do f
. Comparative morphology of Fungi. Fungi. Fig. 372.—Types of aecia. 1. Caeoma of Phragmidium Rubi. P, paraphyses. 2. Aecidium of Uromyces Erythronii. Per, peridium. (1 X 400; 2 X 300; after Sappin- Trouffy, 1896.) lum Sempervivi and Puccinia obtegens (P. suaveolens), they have a sweetish odor, in Gymnoconia Rosae, an offensive odor. Their further develop- ment is unknown. In some species, , Phragmidium violaceum, they appear to degenerate early (Blackman, 1904); in others, as Cronartium ribicola, they appear to be normal (Colley, 1918). In any case, they seldom germinate and when they do form a short germ tube, it is not capable of producing infection. Simultaneously with the pycnospores or shortly thereafter, a second spore form, the aeciospores, usually develops in special sori, the aecia, on the uninucleate mycelium. These belong to two types: the caeoma, which is usually placed directly under the cuticle or epidermis, is broad and flat, naked or covered by periphyses (in the Uredinales, usually called paraphyses, Fig. 372, 1). After its formation it is able to spread laterally and is consequently indefinite in form. In the higher type, the aecidium (or cup type) is placed in the host tissue, several cell layers deep; it is spherical or ellipsoidal and always covered by pseudoperidium, also. 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 may not perfectly resemble the original Gäumann, Ernst Albert, 1893-1963; Dodge, Carroll William, 1895-. New York [etc. ] McGraw-Hill Book Company, Inc.
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