xxv.] CORN MILDEW AND BARBERRY BLIGHT. 175 



have appeared on the rye. The probability of the occur- 

 rence of an alternation of generations on fungi was sug- 

 gested by the Kev. M. J. Berkeley in the Journal of the 

 Royal Horticultural Society for 1848, where he wrote, in 

 describing the "Bunt" fungus of wheat, "It is quite 

 possible in plants, as well as in the lower animals, there 

 may be an alternation of generations." In 1865 Professor 

 A. de Bary, of Strasbourg, published an essay- Monats- 

 hericht der Koniglichen Preuss. AJcademie der Wissenschaften 

 zu Berlin, Jan. 1865 in which he stated that he had arti- 

 ficially produced the rust of wheat by placing the spores 

 of the barberry fungus on corn. One would have natur- 

 ally thought that Professor de Bary was led to make this 

 experiment by his knowledge of the popular belief as to 

 the supposed connection of the two fungi; but we are 

 told by Mr. Plowright in the Gardeners' Chronicle for 30th 

 July 1883 that this was not the case, but that Professor 

 de Bary had previously experimented with a Puccinia, 

 named P. tragopogonis, Corda, and that the little pro-my- 

 celium spores produced by the germinating teleutospores 

 of the Puccinia, when sown on a healthy host-plant, did 

 not produce a Uredo, but an ^Ecidium named JE. tragopo- 

 gonis, Pers., and that when the dEcidium spores were 

 planted on another host-plant, they in turn produced a 

 Uredo. We have in this country an abundance of 

 sEcidium tragopogonis, Pers., but Puccinia tragopogonis, 

 Corda, is unknown. Professor de Bary, then (says Mr. 

 Plowright), selected the barberry " because experience had 

 taught the practical farmer that it was prejudicial to the 

 wheat crop." This admission appears to be identical with 

 the one suggested by us, that the experiments were under- 

 taken in consequence of a popular belief amongst a certain 

 number of farmers and their labourers. Professor de Bary 

 appears to have been unacquainted with the admirable 

 paper by Professor J. S. Henslow in voL ii. of the Journal 

 of the Royal Agricultural Society for 1 84 1 , where the identity 

 of rust or Uredo and mildew or Pucciniawas first pointed out. 



