282 DIVISION 21. COURSE OF DEVELOPMENT OF FUNGI. 



The first species that were more thoroughly studied belong to the latter category. It 

 was natural therefore to begin the account of their life-history with the formation 

 of sporidia, and then the teleutospores form its close ; this is the origin of their 

 name. 



Since the special forms of these teleutospores serve to characterise form-genera 

 which are still preserved in an altered sense, they still bear special names derived 

 from these genera, as Puccinia spores, Triphragmium spores, Phragmidium spores, &c. 

 Tulasne called them simply spores, to distinguish them from the rest. The terms 

 uredo and aecidium at present in use were originally the names of form-genera, 

 and were retained, but with an altered meaning. The fact that almost all the aecidia 

 and uredines, unlike the teleutospores, were included in a single form-genus points 

 to a very great similarity in the forms of the same name, and there is this similarity 

 in fact between most of the aecidia. More minute investigation has already discovered 

 greater variety among the uredines, and especially two chief types in the abjunction of 

 the spores, namely, solitary abjunction on filiform sterigmata, as in Puccinia, Uro- 

 myces, and other genera, and successive serial abjunction, as in Coleosporium and 

 Chrysomyxa. A more considerable^eparture from all others is found in one genus only, 

 Hemileia. 



There is no need to enter here into the details of the combinations which arise from 

 the points of view indicated above and of their application to the determination and 

 grouping of species and genera, since they can be seen quite well in Fungus-floras ; the 

 reader is especially referred to Winter's Pilzflora. 



SECTION LXXXI. Beside the many species of aecidia-forming Uredineae which 

 are now known to us in the whole course of their development, there are a number 

 of forms which resemble them so closely in certain portions of it, that they are 

 regarded without hesitation as their homologues, though their complete life-history 

 has not yet been ascertained. The further development of the stage with which the 

 investigation begins has been followed for a certain distance, but without returning 

 again to the starting-point. It is therefore also still uncertain what kind of organs 

 actually belong to the course of development in each species. Examples of this are 

 found in abundance in the Floras, and include every kind of known organs. In 

 Peridermium elatinum for example, Phelonites strobilina, Aecidium Sedi, and many 

 others we know only the aecidia, in Phelonites strobilina not even the germination of 

 the spores ; this is known in the two other species and agrees perfectly with that of 

 other aecidia which do not form a promycelium, but it is not known how and where 

 the further development of the germ-tubes takes place. The teleutospores only are 

 at present known in some Puccinieae, in Uromyces and Triphragmium echinatum, &c., 

 and their germination has been partly observed, but we have not yet learnt what 

 proceeds from the sporidia. A Fungus, for instance, in which the uredo only is 

 known, is described as Uredo Symphyti, the name Uredo being still inconsistently 

 but intelligibly employed to denote a form-genus ; in the case of some forms included 

 under the form-genus Caeoma (Tulasne), as C. Mercurialis, C. Euonymi, and some 

 others, it is doubtful whether they are to be considered as uredines or as naked 

 aecidia like those of Phragmidium. Species like Melampsora Salicina and M. 

 populina, Coleosporium Campanularum, Hemileia vastatrix, &c. form uredospores 

 and teleutospores, and are reproduced with these spores in unlimited numbers from 

 the germ-tubes of the uredospores. The teleutospores form promycelia with 

 sporidia, but no one has been able to find out what becomes of the sporidia. 



Cases like the one last mentioned on the one hand, and on the other the 



