. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. 136 DIVISION II.—COURSE OF DEVELOPMENT OF FUNGI. The above phenomena close the cycle of development and in some species the course of development is actually limited to them; many observations at least have failed to detect anything further, for example in Pythium vexans and Artotrogus. We may therefore conclude that the essential points in the life-history of the whole group are confined to these phenomena. But in most species there is this difference, that the cours
. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. 136 DIVISION II.—COURSE OF DEVELOPMENT OF FUNGI. The above phenomena close the cycle of development and in some species the course of development is actually limited to them; many observations at least have failed to detect anything further, for example in Pythium vexans and Artotrogus. We may therefore conclude that the essential points in the life-history of the whole group are confined to these phenomena. But in most species there is this difference, that the course of the development is extended by the intercalation of numerous propagative cells, gonidia. In some cases indeed the formation of gonidia is actually a necessary part of the entire development; the germ-tube which proceeds from the oospore developes into. Fig. 63. Cystopus candidus. A mycelium with young oogonia off. B oogonium og with oosphere os and anth^ri- dium an. C mature oogonium og; oospore os. D ripe oospore in optical longitudinal section. E, F, G formation of swarm-spores from oospores; 1 endosporium. Magn, 400 times. a small rudimentary plant, which we may call a promycelium (see on page in), and this produces a few gonidia and then dies, while the gonidia give rise to new perfect fertile plants. This is the case with Phytophthora omnivora and Pythium proliferum which represent the intermediate mode of germination mentioned above. A very large majority of species, the two last-named among the number, form gonidia, not or not only in the way just described as terminal members of a short-lived alternate generation, but as accessory products of every normally developed thallus; the gonidia are usually produced in such large quan- tities as to further the propagation of the species to an enormous extent by their germination, and they have such characteristic forms, that the characters of species,. Please note that these images are extracted from scanned page images
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