BtjaTP. ^^ 



CnAPTER VIII. 



RUSTS. 



UNFOHTUNATBLT, tMs group of fungi con- 

 tains species but too well known for their 

 ravages amongst graminaceous plants, especially 

 the cereals. " Corn-rust," as it is generally called, 

 has a reputation little better than mildew, and it 

 really deserves no better, for it is only another form 

 of that peist of the farm, from the mycelium of 

 which the corn-mildew is at length developed. 

 There are two species very closely allied (doubtless 

 only forms of the same species with different spores) 

 which attack the leaves and culms of growing corn, 

 and, bursting through the cuticle in the manner 

 represented in plate VII. fig. 141 (magnified), give 

 a peculiar rusty appearance to the plant, as repre- 

 sented in plate VII. fig. 140. One of these corn-rusts 

 is botanicaUy named Trichohasis ruhigo-vera (Lev.), 

 or the " true rust Trichohasis ; " the latter, which is 

 the generic name, being a compound of two Greek 

 words {thrix, a hair, and basis, a foundation), on 

 account of the spores being at first furnished at 

 their base with a short, thread-like peduncle, which 

 at length falls away (plate VII. fig. 142). The 

 other corn-rust is Trichohasis linearis, or " line-hke 

 Trichohasis," because the sori or pustules are linear. 



