92 A PLAIN AND EASY ACCOUNT 



Gr., I wrap round), so that all the spores are produced 

 and ripened within a kind of stomach or gaster ; and 

 from this feature the family bears the name of Gastero- 

 mycetes. Every one knows the puff-ball, a spherical 

 pouch, containing, when ripe, an almost impalpable 

 brownish dust, not unlike Scotch snuff, and which 

 mischievous schoolboys delight in puffing in each other's 

 faces. The pouch is the peridium or stomach, and the 

 brown dust the innumerable ripened spores. But puff- 

 balls are not the sole members of this group ; they 

 constitute but one of five orders. 



SUBTERRANEAN FUNGI. 



CERTAIN fungi having such a structure as we have 

 described, are subterranean in habit, and these are in- 

 cluded in the first order under the name of Hypogcei 

 (upo, Gr., under ; gea, the earth). In these fungi the 

 hymenium does not become dusty, but remains perma- 

 nent ; nor does it melt away as in other groups, except 

 when it becomes decayed. Some of these resemble 

 truffles so nearly as to be confounded with them. One 

 species of Melanogaster is sold in the markets of Bath 

 under the name of red truffle, and is therefore edible. 

 This is the only example which has come to our 

 knowledge of a useful species. Melanogaster variega- 

 tus is found under trees, especially in the neighbourhood 

 of beeches, in the south and south-western counties of 

 England, and resembles, externally, a brownish irregular 

 tuber ; internally it is divided into cells by whitish 



