292 THE MICROSCOPE. 



De Bary has also carried out a series of experiments 

 which go far to satisfy him that the sporidia of Puccinia 

 qrammis germinate on the leaves of Berheris^ and that the 

 jEcidium of the Berheris (Plate I. No. 22) is a stage in the 

 cycle of development of Puccinia. Thus, whilst in most 

 Uredines the entire development is carried out upon one 

 and the same nutrient plant, the alternate generations in 

 Puccinia graminis require a change of host. This is a 

 state of things well understood now in the animal kingdom 

 in the Tsenise and Trematoda, but Puccinia graminis is, 

 we believe, the first of the parasitic fungi in which it has 

 been particularly ascertained. Another point of interest 

 is a confirmation of the supposed injurious effect of the 

 proximity of Berheris to corn, which has been denied. 

 De Bary further shows that Ifucor mucedo (the common 

 mould) has three, if not four, different forms of fruit; and 

 that the mould called Thamnidium by Link, or Ascophora 

 elegans by Corda, and the mould described by Berkeley as 

 Botrytis Jonesii, and made into a new genus by Fresenius, 

 under the name of Clicttocladium, are only varieties of the 

 fruit of Mucor wiocedo. Also that yeast, Achi/Ia, Sapro- 

 legnia, and Entomophtlwra or Empusa, are identically the 

 same as Mucor mucedo, consequently that a large reduction 

 is needed in the genera of the mucorini. 



The main interest, however, of De Bary's paper on the 

 fructification of the Ascomycetes, consists in observations 

 on E7'ysiphe Cichoracearum, &c., in which the author 

 traces the origin of the perithecium, from its earliest state 

 up to the formation of the single ascus and spores. He 

 notices two cells as being always present and visible from 

 the earliest period, one of which he conjectures may be 

 the female, and the other the antheridium or male organ. 

 He says that the cell, by the division of which the ascus 

 and its coating are formed, only develops itself when it 

 has been in contact with the antheridium ; and he con- 

 eiders it very probable that impregj^ation is effected by 

 such contact, and that the peiithecium of Erysiphe (ex- 

 cepting the outer wall) is the ^jroduct of such impreg 

 nation. 



De Bary's paper or parasitic fungi was, it appears, 

 undertaken with a view to contribute to the solution of 



