Fungi, Ascomycetes, Ustilaginales, Uredinales . that an exceedinglystrong ring unites the antheridium and trichogyne, and they can be bentor turned upon each other without being pulled apart. This arrangementis no doubt necessary to withstand the strain set up by the flow of nucleifrom the relatively wide cavity of the antheridium through the narrow poreand beak. IV I PEZIZALES 105 While the formation of the pore is in progress the nuclei of the tricho-gyne degenerate, and, by the time that they are completely disorganized, a migration of the male nuclei through the pore begins. Ultimately the
Fungi, Ascomycetes, Ustilaginales, Uredinales . that an exceedinglystrong ring unites the antheridium and trichogyne, and they can be bentor turned upon each other without being pulled apart. This arrangementis no doubt necessary to withstand the strain set up by the flow of nucleifrom the relatively wide cavity of the antheridium through the narrow poreand beak. IV I PEZIZALES 105 While the formation of the pore is in progress the nuclei of the tricho-gyne degenerate, and, by the time that they are completely disorganized, a migration of the male nuclei through the pore begins. Ultimately thecontents of the trichogyne degenerate still further, till the cytoplasm andnuclei together form a densely staining mass which maybe recognized evenin the mature fruit. The male nuclei continue to pass into the tube until itis densely filled, and sometimes a trifle swollen. According to most observersthe wall at the base of the trichogyne now breaks down so that an openpassage is formed and the male nuclei travel through (fig. 63a), and mingle. Fig. 63. Pyronema confluens; a. entrance of male nuclei into oogonium, x 14.^=: b. association ofmale and female nuclei, xitfjo; <• ascogenous hyphae with nuclei in pairs, X820; after()laussen. with the female nuclei. After their migration is complete a fresh wall islaid down across the base of the trichogyne, cutting off the oogonium oncemore as a single spherical cell. The female nuclei meantime become aggregated together (fig. dia) andform a hollow sphere or dome or a sickle-shaped group. This is no doubta provision for insuring their association with the male nuclei with thegreatest certainty and dispatch. According to both Harper and Claussen, the sexual nuclei now pair;I [arper has recorded complete fusion at this stage (fig. 62b), while Claussen(fig. 636) regards the nuclei as merely associated in preparation for theirultimate union in the ascus. Dangeard, on the other hand, denies the dis-appearance of the wall between the oo
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectfungi, bookyear1922
