. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. 72 DIVISION I.—GENERAL MORPHOLOGY. one belonging to the sixth youngest spore in the chain. Phenomena essentially the same occur in other species of the Uredineae, but with considerable variations in form in the different species'. Where filiform sporophores rise free into the air, a further mechanical arrange- ment is found which greatly assists the shedding and scattering of the abscised spores. It may be readily observed in the Hyphomycetes, in Peronospora, for exam
. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. 72 DIVISION I.—GENERAL MORPHOLOGY. one belonging to the sixth youngest spore in the chain. Phenomena essentially the same occur in other species of the Uredineae, but with considerable variations in form in the different species'. Where filiform sporophores rise free into the air, a further mechanical arrange- ment is found which greatly assists the shedding and scattering of the abscised spores. It may be readily observed in the Hyphomycetes, in Peronospora, for example, Phytophthora infestans, and in the gonidiophores of Peziza Fuckeliana, &c. The hyphae of these Fungi are cylindrical in the moist and turgescent state, but collapse when dry and especially when the spores are ripe into a flat ribbon-like form'', and the drier they are the more strongly do they become twisted round their own longitudinal axis. They are so highly hygroscopic that the slightest change in the humidity of the surrounding air, such for instance as may be caused by the breath of the observer, at once produces changes in their turgescence and torsion; the latter give a twirling motion to the extremity of the gonidiophore and the ripe spores are thereby thrown off in every direction. Abjection of acrogenous propagative cells is effected by a mechanism which we shall have to speak of again in section XXI. The cell which is to be abjected, whether spore or spore-mother-cell (for brevity we shall call it spore), is abjointed singly by a cross septum at the apex of a tubular and often comparatively large sporiferous cell, a basidium or a sterigma, which retains its parietal protoplasm still intact after the abjunction of the spore and is still turgescent in consequence of a continued FIG. 38. Piioboim cedifus, Mont supply of Water in increasing quantity. Its membrane DiagTaromatical representation of a iii- 1. longitudinal section; t upper end of IS highly cxteHs
Size: 1116px × 2240px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, bookpublisheroxfor, bookyear1887
