174 



INTRODUCTION TO THE STUDY OF FUNGI 



sometimes called, may be hairy, woolly, granular, or quite 



smooth (Fig. 69). 



The inner stratum, or disc, has quite a different structure 



from the outer stratum, or excipulum, being composed, of a 

 series of elongated, delicate cells like 

 ?j(\ if ~'~ "~^*li cylinders, closely packed side by side, 

 Dll vv ~*s\s*J J) their apices terminating in the disc, 

 and their bases being seated upon the 

 inner surface of the excipulum (Fig. 70). 

 In due time these cylindrical sacs, or asci, 

 contain four or eight, or some multiple 

 of that number, of smaller bodies, which 

 are the spores or sporidia — the repro- 

 ductive corpuscles of the Fungus. In 

 some cases the apex of the ascus opens 



fig. 69.— Cup of Praiza, with ^„ means f an operculum, or small 



section and ascus. , . , , , , , , . , 



lid, but at others by an irregular rup- 

 ture, to permit of the escape of the spores. : Mixed with 

 these spore-bearing sacs will be found a number of long 

 thread-like bodies of equal length, or longer than the asci, and 

 these are termed paraphyses. Some mycologists believe them 

 to represent abortive 

 asci, and this is sup- 

 ported by the fact that 

 now and then a para- 

 physe is observed which 

 encloses one or two 

 spores, like the normal 

 spores of the Fungus. 

 When the Peziza is 

 young, and the cup is 

 closed, a-11 the cylindri- 

 cal cells are narrow, thread-like, and empty ; but as growth pro- 

 ceeds and sporidia begin to form, the diameter of the cells 

 increases, and, as a consequence, the disc enlarges and expands 

 with the lateral pressure so as to occasion the flattening out of 

 the cup. "When there is a great expansion the edges of the cup 

 are either split or bent back, so that the disc becomes convex, 

 all these modifications being due to the thickening of the asci. 



Fig. 70. — Section of cup of Ascobolus. 



