Fungi, Ascomycetes, Ustilaginales, Uredinales . ear and fourbasidiosporcs are produced, which, in due course, give rise to a uninucleatemycelium. The sporophytic stage thus endures only from the fusion of thefertile cells until the germination of the spores which they produce. Incidentally these observations in the case of Kunkelia nitens havedemonstrated that the caeoma of this fungus is not a stage in the life-historyof the teleutospore-producing Puccinia Peckiana on the same host, for themycelial cells of/. Peckiana are binucleate and the teleutospores germinatein the usual way. The develop
Fungi, Ascomycetes, Ustilaginales, Uredinales . ear and fourbasidiosporcs are produced, which, in due course, give rise to a uninucleatemycelium. The sporophytic stage thus endures only from the fusion of thefertile cells until the germination of the spores which they produce. Incidentally these observations in the case of Kunkelia nitens havedemonstrated that the caeoma of this fungus is not a stage in the life-historyof the teleutospore-producing Puccinia Peckiana on the same host, for themycelial cells of/. Peckiana are binucleate and the teleutospores germinatein the usual way. The development of an apo-gamous aecidium has been ob-served by Moreau in a varietyof Eiidopliyllitm Euphorbiae onEuphorbia sylvatica; here thebasal cells, aecidiospores andcells of the pseudoperidium areuninucleate throughout theirdevelopment, the aecidiosporegerminates to form a promy- Celium Of three or four cells Fi§- ,s7- Endophyllum ivi Lev.; a. nuclear fusion iii spore; b. synapsis in fusion nucleus; afterand neither nuclear association 4 2io PROTOBASIDIOMYCETES [ch. nor nuclear fusion takes place at any stage, the diplophase being whollyomitted. Heteroecism. In many rusts the gametophytic and sporophytic myceliaoccur on different host plants. Such forms are termed heteroecious incontrast to the autoecious species where the whole life-history is passedon a single host. It is not surprising that the different spore forms on suchspecies were recognized and described some time before it was understoodthat they are stages in the life-history of a single fungus. The final proofof the relationship of the aecidia and spermogonia on the one hand and theuredo- and teleutosori on the other, was given by de Bary in 1865 forPuccinia Graminis, the wheat rust or, as the teleutospore stage was calledby early investigators, the wheat mildew. In this plant the haplophase occurson the leaves of the Barberry (Berberis vulgaris) and the diplophase onwheat, oats, rye and other grasses
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectfungi, bookyear1922
