xlii PROCEEDINGS OF THE 



eeeds to describe the production by the oospores (or impregnated 

 contents of the oogonia) of active zoospores, similar to those 

 produced by the ordinary spores of Cystopus, Dr. de Bary states 

 that these zoospores, after remaining active" for three or four 

 hours, lose their cilia and power of motion, assume a cellulose 

 covering, and germinate. He adds that the germ-filaments enter 

 readily by the stomates and leaves of the nutrient plant, but that 

 those filaments only become developed which enter the stomates 

 of cotyledons. In Feronospora the development of the antheri- 

 dia, oogonia, and oospores is said by De Bary to be the same as 

 in Gystopus ; and he gives particulars of the mode of germination 

 of the conidia, and remarks on the growth of the parasite, which 

 can only be studied in detail in the paper itself. 



The most interesting part of the paper is that which contains 

 the observations on Uroinyces appendiculatus. The mode of ger- 

 mination of the spores of this plant, the growth of the promyce- 

 lium, and the production of the so-called sporidia are well known 

 from Tulasne's account *, published long since in the Annales des 

 Sciences IsTaturelles. De Bary has followed the process in its sub- 

 quent stages. According to his observations, the sporidia pro- 

 duce a mycelium, from which spring in succession — 1st, spermo- 

 gonia ; 2ndly, peridia, producing chains of orange-coloured fruit 

 {or, in other words, an ^cidium) ; and 3rdly, the original fruit of 

 Uromyces, accompanied by the more simple fruit formerly called 

 Uredo, and now called C7re(?o-stylospores. The germination of 

 the -^a'J^MOT-stylospores (*. e. the fruit produced by the peridia), 

 as well as that of the CTireio-stylospores, produces, according to De 

 Bary, 1st, C/ret^o-stylospores, and, 2ndly, the original Uromyces- 

 spores. These results, if correct, are very singular. We find the 

 TTromyces-s^ore^ passing through the generations of promyce- 

 lium, sporidia, and mycelium, — the latter producing successively 

 the two difi'erent products, spermogonia and secidia, and ulti- 

 mately the original fruit of Uromyces, accompanied by the Uredo. 

 The spermatia (or contents of the spermogonia) never germinate; 

 but we find the fruit of the secidia, and also of the Uredo, repro- 

 ducing, first the Uredo itself, and subsequently the original fruit 

 of Uromyces. 



Other interesting points noticed by De Bary are, that not 

 only has each species of parasite a certain special nutrient plant, 

 but it is probable that in certain Uredinese with multiple fruit 



■* " Second Memoire sur les Uredinees et les Ustilaginees," Ann. d. Sc. ser. 

 4. vol. ii. p. 77. 



