6 MICEOSCOPIC rUNGI. 



because in this, and many other instances, the 

 specific name of the fungus is derived from the 

 plant, or one of the plants, upon which it is found, 

 that therefore the species differs with that of the 

 plant, and that, as a rule, he may anticipate meet- 

 ing with a distinct species of fungus on every 

 distinct species of plant, or that the parasite which 

 he encounters on the living leaves of any one plant 

 is necessarily specifically distinct from those found 

 on all other plants. One species of ^cidium, for 

 instance, may hitherto have been found only on one 

 species of plant, whereas another Mcidiwm may 

 have been found on five or six difierent species of 

 plants. The mycologist will look to the specific 

 differences in the parasite without regard to the 

 identity or distinctness of the plant upon which it 

 is parasitic. 



Before the ^cidium breaks through the epi- 

 dermis, the under-surface of the leaves of the 

 goatsbeard wiU appear to be covered with Httle 

 elevations or pustules, paler at the apex ; these 

 soon become ruptured, and the fungus pushes its 

 head through the opening, at the same time 

 bursting by radiating fissures. The teeth thus 

 formed resemble those of the peristome of some 

 mosses. AU around the orifice of the peridium 

 the teeth become recurved, and the orange spores 

 are exposed, crowded together within. At first, 

 and while contaiaed within the peridium, these 

 spores are concatenate or chained together, but 



