2(J8 PROFESSOR MOHL ON 



especially as regards the propagation of the parasite, I turned my 

 attention to the allied fungals, which I found on a multitude of other 

 plants. A special detail of these inquiries is now superfluous, 

 since Monsieur Tulasne has published his own similar observa- 

 tions (Bot. Zeit., 1853, Comiit. Bend., Oct. 17, 1853). A short 

 indication nevertheless of the result at which I have arrived will 

 not be entirely undesirable. This consists, in a few words, of the 

 fact that Oidium Tuckeri is an Erysiphe, since it not only agrees 

 with Erysiphe in the organisation of the mycelium, but the 

 fructification discovered by Amici on the Grape-mildew is found 

 also on a considerable number of Erysiphes. 



A. Berenger was the first who,''' on an investigation of the 

 vegetative organs of the Vine-mildew, pronounced it an Erysiphe 

 {II Coltivatore, 1852, no. 14); but, inasmuch as he did not know 

 the fructification of the fungus, and arrived at the somewhat 

 adventurous conclusion that the Oidium Tuckeri is a chimera 

 and nothing more than Erysiphe communis, his views obtained 

 no followers: notwithstanding, this ill-grounded but lucky conclu- 

 sion did in point of fact indicate the then systematic position of 

 the fungus in question. 



I first discovered in Sphserotheca Castagnei, Lev., growing on 

 the leaves of the common Hop, that the fructification found by 

 Amici in Oidium Tuckeri could not be considered the character- 

 istic form of fruit of the new genus of fungi proposed by 

 Ehrenberg under the name of Cicinobolus (Bot. Zeit., 1853, 

 p. 16), but exhibited a mode of reproduction which existed on 

 one and the same plant at the same time with the oval germina- 

 tive cells which become disjointed from the upright threads of the 

 mycelium and agree with the well-known secondary fruit of 

 Erysiphe. This species exhibited a peculiarity, which I also 

 detected in others at a later period ; viz., that in one place one 

 form of fructification only occurred, in another place another form 

 more especially ; thus at Etschthal I found only the Cicinoboloid, 

 at Insterthal more especially the Erysiphoid form. Similar 

 relations obtained in Calocladia Berberidis, Lev., of which I found 

 at Bozen only the Erysiphoid fruit, while at Meran the Cicino- 



* The possibility of this is poiuted out in the Gardeners' Chronicle, July 

 28, 1849, where it is stated with respect to the Grape and Peach mildew 

 &c. "It is still a botanical doubt whether all these egg-seeded mildews are 

 not simply early stages of the genus Erysiphe, as is certainly the case with 

 that of the Hop." Even in the original article on Oidium Tuckeri, Nov. 27, 

 1847, the relation of such productions is expressly indicated, and other 

 analogous cases brought forward. — Tr. 



