58 



that division than with other fungi ; but they are known 

 only to us under one form, which may be considered to be 

 that in which they produce conidia." De Bary instances 

 the common " Cladosporium herbarum, Lk. as among the 

 forms which never produce anything but mycelium with 

 serially abjointed conidia. Sorauer terms these chain-like, 

 kettenartig.* 



Cladosporium herbarum Link, synonymous with Dematium 

 herbarum, is the conidiophore stage of Sphwria herbarum 

 whose synonym according to Tulasne is Pleospora herbarum.^ 



Other forms or stages of 8pho3ria, or Pleospora herbarum, 

 are Macrosporium sarcinula, Berkeley, and what is termed by 

 De Bary the Alternaria form, which consists of " conically pear- 

 shaped pluricellular compound spores, having a smooth light 

 brown membrane, and arising at the extremity of the hyphce 

 in long branched rows." 



Though at some risk of creating confusion, it is important to 

 deal with the various forms of this fungus, and to endeavour to 

 identify them and their host plants, in order, if possible, to 

 discover means to prevent its spread in the stage dangerous 

 to corn. A Macrosporium, called Macrosporium commune, 

 (Rabenhorst) on leaves of beet, is said by Berkeley to be probably 

 a condition of Sphoeria 'herbarum ; and Macrosporium brassiccv, 

 upon the leaves of decaying cab bages and of other cruciferous 

 plants, is said by Cooke in his handbook of British Fungi to be 

 intermixed with Cladosporium herbarum, " of which it is pro- 

 bably a condition." Dr. Comes, Professor of- Botany at the 

 Royal School of Agriculture at Portici, says, that Clados- 

 poriwm> herlarum has been found on the leaves of turnips, 

 and in favourable circumstances reproduces Pleospora her- 

 barum.\ Trumen also reports the same of some experiments in 

 Bohemia. 



Mr. Carruthers, however, believes the fungus which did so 

 much harm to wheat and barley this year in Norfolk and else- 

 where is identical with Scolicotrichum graminis, which has 

 been placed by some botanists in the species Cladosporium, 

 herbarum. 



Dr. Lopriore has recently recorded a series of most interesting 

 experiments with Cladosporium herbarum. Among these 

 were three, in order to ascertain : 



1st. Whether artificial infection of sound corn plants with the 



fungus produces destructive results. 



2nd. Whether corn plants attacked by the fungus are 

 contagious. 



* Op. Cit., p. 231. 



t De Bary remarks: "Even if Tulasne's view that the Cladosporium herbarum 

 " belongs to Pleospora herbarum is not confirmed, its connection with one of the 

 " allied Spkceriacea is more than probable." Op. cit., p. 67. 



J Crittogamia agraria, par Dr. O. Comes, 189J.. 



Deutsche Landwirtschaftliche Presse, No. 86. 



