. Comparative morphology of Fungi. Fungi. OOMYCETES 67 until only a thin protoplasmic wall layer with few nuclei remains (Fig. 40, A). The nuclei then undergo simultaneously a single mitotic division and degenerate; finally the protoplasm splits, rolls up around each of the remaining nuclei and forms uninucleate eggs, oospheres (Fig. 40, D). At first the egg nucleus shows a rostrate process with a definite centrosome. <^d. Fig. 40.—Saprolegnia monoica. Egg development. A, young oogonium with periph- eral protoplasm; B to D, sections of the peripheral layer in different stages of develop- me
. Comparative morphology of Fungi. Fungi. OOMYCETES 67 until only a thin protoplasmic wall layer with few nuclei remains (Fig. 40, A). The nuclei then undergo simultaneously a single mitotic division and degenerate; finally the protoplasm splits, rolls up around each of the remaining nuclei and forms uninucleate eggs, oospheres (Fig. 40, D). At first the egg nucleus shows a rostrate process with a definite centrosome. <^d. Fig. 40.—Saprolegnia monoica. Egg development. A, young oogonium with periph- eral protoplasm; B to D, sections of the peripheral layer in different stages of develop- ment; c, normal nucleus with centrosomes; d, degenerating nuclei. (After Claussen, 1908.) Meanwhile the antheridium has approached the oogonium and partially surrounded it. About simultaneously with that of the oogo- nium, the nuclei divide once. Hereupon the antheridia pierce the oogonial membrane through pits. Within the oogonium the process divides,into several branches, each of which approaches an egg cell and discharges a nucleus into it. Nuclear fusion follows immediately. The fertilized egg surrounds itself with a two-layered, smooth, colorless membrane: it becomes an oospore with the character of a 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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Keywords: ., bookcentury1900, bookdecade1920, bookpublishern, booksubjectfungi
