S8 MICEOSCOPIC FTJNGI. 



termed a genus, and the term prefixed to the specific 

 name of each species constituting that genus is its 

 generic name, also commonly derived from the 

 Latin or Greek. In this instance it is Pucci/nia, 

 derived from the Greek jpuha, meaning closely 

 packed, singularly appUcahle to the manner in 

 which the spores are packed together in the pus- 

 tules. The common features, or generic distinc- 

 tions, of this genus, are uniseptate spores borne on 

 a distinct peduncle. 



In returning to the species found on Labiate 

 plants, let us suppose ourselves to have strolled 

 towards Hampstead Heath, and south of the road 

 leading from Hampstead to Highgate, near certain 

 conspicuous and well-known arches, buUt for a pur- 

 pose not yet attained, are two or three muddy 

 ponds nearly choked up with vegetation. Some 

 fine autumnal afternoon, we must imagine ourselves 

 to have reached the margin of the most northern of 

 these ponds, and amidst a thick growth of reeds, 

 sedges, and other water-loving plants, to have 

 found the water-mint in profusion and luxuriance, 

 with every leaf more or less occupied, on its under 

 surface, with the yellow spores of a species of rust 

 {Trichobasis) mixed with the browner septate spores 

 of the miut brand (Puccinia Menthce) . This is com- 

 mon also on the horse-mint and corn-mint ; we 

 have found it on the wild basil and wild thyme, 

 and once only on marjoram. Having collected as 

 many leaves as we desire, and returned to home 



