112 PRIZE ESSAY : 



rishment which should be appropriated by the growing grain. 

 Before proceeding further with a description of ' rust/ it is 

 essential to acquire information respecting the structure, mode of 

 growth and reproduction of the tribe of vegetables called fungi. 



Mildew is occasioned by a minute fungus called Puccinia 

 Graminis. 



Rust is the growth of two kinds of fungi, uredo rubigo and 

 uredo linearis. It is probable that the rust of this country dif- 

 fers from the ' rust ' in England, certainly there is a great differ- 

 ence between the appearance of the fungus on growing wheat 

 stems here, and the delineations given in European works on 

 this subject. 



Smut, is uredo segetum. 



Bunt, is uredo fcetida ; 'stinking rust.' 



199(a). Many other fungi prey upon other vegetables. Mr. 

 Berkeley thought that the potato disease was due to a parasitical 

 fungus found in the haulm, the botrytis infestans. Martius also 

 ascribed the potato malady to a fungus, differing from the one 

 last named. 



_^a 



(3) 



(1) 

 SECTION AND PORTION OP A STALK OF WHEAT AFFECTED WITH RUST. 



(1) (1) (I) Masse? of the Rubigo. (2) Stomata, or breathing pores, (3) Cellular 

 tissue. (4) Cuticle. (5) Epidermis. 



