ASCOMYCETES 125 



type is called an ascostroma. In the liigher forms the hyphal tissue of the 

 stroma undergoes differentiation both in form and histologic structure, and 

 develops the fructifications which furnish important characters for classifica- 

 tion. Only one of these structures in its simplest form need concern us here. 

 For a further consideration of the higher Ascomycetes see Gaumann & Dodge 

 (1928) and the recent fundamental work of Nannfeldt (1932). 



The perithecium consists of a solid, often pseudoparenchymatous wall 

 and a cavity in which the asci are borne (Fig. 12, 7). The more primitive 

 types are usually spherical ; the asci lie irregularly in the interior and are only 

 liberated by the decay of the perithecial wall. In the higher types, there are 

 more elaborate mechanisms for spore dispersal. 



BIBLIOGRAPHY 



Gaumann, Ernst A. & Carroll William Dodge. 1928. Comparative morphology of fungi. 



New York, McGraw Hill Book Company, 701 pp., 398 jigs. 

 Nannfeldt, J. A. 1932. Studien iiber die Morphologic und Systematik der nicht-lichenisierten 



inoperculaten Discomyceten, Nova Acta E. Soc. Sci. Upsaliensis IV, 8: 2:1-368, 



Pis. 1-20. 



