RUSTS. 109 



occurs on the little purging flax (Linum catharticum), 

 forming small pustules on the leaves (plate VIII. 

 fig. 165) ; these burst irregularly, and remain sur- 

 rounded by the remains of the ruptured epidermis 

 (plate VIII. fig. 166). The yellowish spores are 

 subglobose (plate VIII. fig. 167), and in the first 

 instance concatenate, or chained together like a 

 necklace, which circumstance has been taken ad- 

 vantage of to place it, with one or two other species, 

 in a separate genus. 



We cannot claim for the species brought into 

 notice in the present chapter any attractive features 

 resulting from singularity of form, complexity of 

 structure, or delicate tracery, whereby they might 

 commend themselves to mere " searchers after 

 curiosities," or be recommended from friend to 

 friend as " sensation" objects for the microscope. 

 They do possess an interest and a value, but such 

 as would not be appreciated by those who seek 

 to pass an idle half-hour by gazing at some new 

 thing. 



