34 MICEOSCOPIC FUNGI. 



in tlie season are produced upon the same mycelium, 

 and are indeed aggregations of more perfect and 

 complex fruits of tlie same plant. Before this 

 point was satisfactorily decided, the brown spores, 

 which are borne on long stalks, and are themselves 

 septate or divided (apparently or really) by trans- 

 verse partitions into a complex fruit, received 

 the name of Puccinia Rosoe. At this period, Uredo 

 BoscB and Puccinia Rosoe, or the yellow fungus and 

 the dark brown fungus, were believed to be dis- 

 tinct and different plants ; now, on the contrary, 

 they are believed to be different forms of fruit 

 produced by the same plant ; i.e., an instance of 

 di-morphism. Aregma mucronatv/m, Fr., is the 

 present scientific name of what is regarded as the 

 perfect fungus, whilst the uredo-form either bears 

 the name of Leeythea Rosoe, Lev., or by some 

 mycologists is rejected altogether as a spurious 

 species. 



During the summer it is not uncommon to find 

 the leaves of some grasses, of the hop, of roses, 

 and many other plants, covered with a kind of 

 white mould, which appears under the microscopo 

 as a multitude of small transparent colourless 

 cellules, generally attached to each other in a 

 monihform or beaded manner. These moulds were 

 long known under the generic name of Oidium, to 

 which genus the vine disease was also referred. 

 More minute investigation and more careful 

 examination proved that these moulds were not in 



