IN THE VEGETABLE KINGDOM. 43 



as Dilophosporium, Neothosporium, and Pestalozzia, where 

 the objects are of some interest on account of their curious 

 appendages. All, indeed, are interesting so far as ascertained 

 dualism is concerned, or as far as there may be a prospect 

 of shewing that they are the spermagonia or pycnidia of 

 ascophorous species."* 



This relation of associated forms may be illustrated by 

 the development of JEcidium. The spores of this fungus 

 produce a mycelium, the filaments of which bear the naked 

 spores of the Uredo, and these, when they come to germinate, 

 originate a second mycelium, in connection with which are 

 developed spermatia and the thecaspores of the JEiddium.^ 



It is possible that in some species without spermatic 

 fruit particles of a similar kind may be developed from 

 certain of the spores, by an arrangement like that described 

 by Pringsheim in the androspores of (Edogonium, for in the 

 germination of certain fungi it has been observed that 

 while some of the spore-like bodies emit mycelial threads, 

 others give origin to minute corpuscules, which undergo no 

 farther development. These have been conjectured to be of 

 a spermatic nature. J In some species of Peziza, according 

 to Radlkofer, a process of this kind occurs, while in others 

 the corresponding bodies originate the spermatic particles 

 less directly by the intermediate development of a special 

 spermatiferous mycelium. 



This may be considered as a sort of alternation of genera- 

 tions ; and it is to be observed that it occurs in the gamo- 

 morphic stage of development, that is, in the maturation of 



* Introd. to Cryptogamic Botany, p. 331. 



f Tulasne, as quoted before. Sometimes the succession is complicated 

 by other intermediate forms ; thus in the germination of some species of 

 Erysiphe a succession of mycelial forms are produced from sporoid bodies 

 of different kinds, and the series is closed by the development of the 

 sporiferous thecse. 



J Curreyin Journal of Micros. Science (April, 1857), pp. 124-126. 

 Radlkofer Ann. Nat. Hist., 2d Ser., XX., p. 247. 



