. The British rust fungi (Uredinales), their biology and classification. Uredineae. 12 TELEUTOSPORES is much thicker at the apex than elsewhere (Fig. 13). While the spores are standing in a densely crowded sorus, the apex is the part most exposed to the weather, and therefore most needing protection. There is a thin endospore to each cell: the contents are granular and at first oily; there is a large and conspicuous nucleus in the centre of each. This nucleus, in its resting stage, is almost homogeneous except for its nucleolus, and was mistaken by the older observers for a "
. The British rust fungi (Uredinales), their biology and classification. Uredineae. 12 TELEUTOSPORES is much thicker at the apex than elsewhere (Fig. 13). While the spores are standing in a densely crowded sorus, the apex is the part most exposed to the weather, and therefore most needing protection. There is a thin endospore to each cell: the contents are granular and at first oily; there is a large and conspicuous nucleus in the centre of each. This nucleus, in its resting stage, is almost homogeneous except for its nucleolus, and was mistaken by the older observers for a " ; Since the mycelium from which the teleuto- spores, as well as the uredospores, were formed contains paired nuclei, the cells of the teleuto- spore were at first in the same condition. When its wall, however, begins to thicken, when it is becoming mature, the conjugate nuclei unite, and form one large fusion- nucleus (Fig. 14). The two fusing nuclei, after the very Fig. 13. Teleuto- spore of P. Caricis. x Fig. 14. Formation of teleutospores of P. Falcariae (after Dittschlag); a, the spore-bearing hypha; b, the same divided into pedicel and spore-cell; c, the spore divided into two cells ; d, a young teleuto- spore ; e, the same after the fusion of the nuclei, x about 800. numerous conjugate divisions during the long period of gTowth from the formation of the fusion-cell of the gecidium, would be related, as it were, like very distant cousins, especially since the nuclear divisions during this period, though indirect, appear to show a very simplified form of mitosis, tending rather to be of the nature of amitosis. The fusion, as already intimated, is not to be considered as the act of fertilisation, but merely as a necessary preliminary to 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 ori
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishercambr, bookyear1913
