330 



GENERAL MORPHOLOGY OF PLANTS 



forms in which the fertile interior tissue is elevated at maturity 

 by an expanding structure called a receptacle, leaving the wall at 

 the base in the form of a sac-like volva. 



COMPARATIVE REVIEW OF THE FUNGI.* 



482. The three general types of fructification. While 



there are great variations in the special methods in the fruiting 



of the fungi, i.e., in the pro- 

 duction of the spores, they 

 can all be assembled into 

 three general types cf fruc- 

 tification. In each of these 

 types of fructification there 

 are spore-bearing structural 

 elements in the fruit bodies, 

 which are peculiar to the 

 fungi possessing that method 

 of fructification. These are 

 as follows: ist, the spore 

 case (sporangium) in the Class 

 Phycomycetes; 2nd, the sac 

 (ascus} in the Class Ascomy- 

 celes; and 3rd, the basidium 

 in the Class Basidiomycetes. 



483. The Class Phy- 

 comycetes. The members 

 of this class include the forms 

 in which the spore case is the 

 characteristic fruit structure. 

 Together they make up the 

 sporangium series or spore 

 case series of the fungi. The spore case contains the spores, and 

 is for the most part what is called a generalized structure, because 

 it contains often a large and usually a variable number of spores 

 even in the same species. A generalized structure is, in all organ- 



* For reference. 



Fig. 291. 



"Stink horn," or "buzzard's nose" (Dic- 

 tyophora duplicata). X i diameter. 



