THE SPORE AND ITS DISSEMINATION. 



135 



posed, in which the sporidium (as in Perisporium vulgare) 

 consists of four coloured ovate joints, which ultimately separate. 

 Multiseptate fenestrate sporidia are not uncommon in Oueurhi- 



m 

 f 



Pio. 75.— Sporidia of Fio. 76.— Spori- Fia. 77 



Valsa taltola. x 400. dium of Sporormia 



intermedia. 



taria and Pleospora, as well as in Valsa fenestrata and some other 

 species. In the North American Sphwria putaminum the sporidia 

 are extraordinarily large. 



The dissemination of the sporidia 

 may, from identity of structure in the 

 perithecium, be deemed to follow alike 

 method in all. When mature, they are 

 in a great measure expelled from the 

 mouth of the perithecia, as is evident 

 in species with large dark sporidia, 

 such as exist in the genera Hypoxylon, 

 Melanconis, and Massaria. In these 

 genera the sporidia, on maturity, may 

 be observed blackening the matrix 

 round the mouths of the perithecia. 

 As moisture has an evident effect in producing an expul 



FtG. 78. — Sporidium of SpJaxria 

 pvtaminum. x 400. 



