12-4 MICROSCOPIC FUNGI. 



CHAPTER X. 



WHITE RUSTS. 



ALLUSION has already been made to the im- 

 portant memoir recently pubHshed by Dr. de 

 Bary. '' ^Yhite rusts '* occupy a conspicuous posi- 

 tion in that memoir, and the experiments therein 

 detailed, with the conclusions arrived at, will be 

 largely drawn upon in furnishing the present chap- 

 ter. Whilst believing that we have fairly repre- 

 sented the views, and faithfully narrated the story 

 of research, if not literally, but denuded of some 

 technicahty, yet in such manner as to convey the 

 sense of our author, we claim no originality or 

 merit save for the garb in which it appears, without 

 addition, stricture, or confirmation of our own. 



AMiat is the external appearance presented by 

 the " white rust '^ of cabbages, and allied cruci- 

 ferous plants, is soon told. During summer and 

 autumn it occupies the surface of the leaves and 

 stems of the shepherd^s purse {Capsella hursa-pas- 

 toris), with elongated narrow white spots like 

 streaks of whitewash (plate X. fig. 198), and later 

 in the season the leaves of cauliflowers and cab- 

 bages become ornamented with similar patches, 

 arranged in a circular manner (plate X. fig. 199), 

 forming spots as large as a sixpence. Wherever 



