102 MICROSCOPIC FUNGI. 



the presence of a peduncle in the early stage of 

 Trichobasis (plate VII. fig. 169), and its absence 

 in all stages of Uredo. Without wandering fur- 

 ther into a subject which has not the merit of 

 bein^f very popular_, let us away to some green 

 lane in search of violets, and having found them, 

 take a little of the brown dust from one of the 

 small pustules on the leaves, upon the point of a 

 penknife ; place this, with a drop of water, upon a 

 glass slide, and make a record of what we obser^^e. 



The field is covered with the myriad spores of a 

 rust of a nearly spherical shape, brownish in colour, 

 and here and there one with a short transparent 

 colourless stalk or pedicel. This is the violet rust 

 (Trichobasis Violarumj^.)jYerj common all through 

 the summer and autumn, generally on the under 

 surface of the leaves of violets, in woods and 

 hedgerows. Should it so happen that the spores 

 when placed under the microscope are found to be 

 two-celled, it will prove that instead of a rust, or 

 Trichobasis y being under examination, a brand, or 

 Puccinia, has been found, which is almost equally 

 common, and which may, without such a test, be 

 easily mistaken for a rust. According to the theory 

 of di-morphism, this is the higher form or complete 

 fruit of the same fungus, which in its simple- celled 

 state is called Trichobasis Violarum. 



A similar circumstance may befall the student in 

 examining the rust of labiate plants {Tricliobasis 

 Labiatarur/ij Lev.), which occurs on difi'erent species 



