Nature and development of plants . ls (Figs. 156, 158) ; the black knot of the cherry and plum trees (Fig. 150), and the ergot of rye, etc. The mycelium resembles in structure that of preceding orders,but its hyphae are composed of numerous cells instead of beingtubular as in the Phycornycetes (Fig. 138). The sporangia () are reduced in size and contain but a single spore each,which is never discharged from the sporangium. This body willbe referred to in the future as a spore or conidium (plu. conidia). The gametangia are often suggestive of those of the downymildews (Figs. 147, A; 157)
Nature and development of plants . ls (Figs. 156, 158) ; the black knot of the cherry and plum trees (Fig. 150), and the ergot of rye, etc. The mycelium resembles in structure that of preceding orders,but its hyphae are composed of numerous cells instead of beingtubular as in the Phycornycetes (Fig. 138). The sporangia () are reduced in size and contain but a single spore each,which is never discharged from the sporangium. This body willbe referred to in the future as a spore or conidium (plu. conidia). The gametangia are often suggestive of those of the downymildews (Figs. 147, A; 157), though in many forms they appearto be lacking. The fusion of the gametes results in the forma-tion of a gametospore which germinates at once, forming in the 206 NATURE OF THE SAC FUNGI simplest cases one or more sacs. These bodies are known as asci(sing-, ascus) and they contain more frequently eight spores,called ascospores (Fig. 141), which must be distinguished fromthe spores or conidia mentioned above. The gametospore germi-. Fig. 138. The green mould, Pciiicilliinn, one of the most common of theSac Fungi. The hyphae of the branching mycelium is composed of cellsand the spores or conidia are formed in chains that are arranged in brush-like clusters at the ends of the erect hyphae. nates as a parasite on the mother plant as in the red sexual process results, in the majority of forms, not onlyin the formation of asci, but numerous hyphae from the my-celium are also stimulated to growth and become associatedwith the asci in various ways. As a result bodies of variousforms, called ascocarps or perithecia, are developed which oftenbecome the conspicuous part of the fungus (Figs. 143, 144).The ascospores germinate immediately or after a period of restand form a new mycelium. It should be stated that the asco-carps have not been connected, in many cases, with sexual proc-esses, and it is inferred that sexuality has been lost along withother characters as a consequence
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