GENERAL FEATURES OF THE TxROUP 



The (Tcneral features of this group were treated under a num- 

 ber of subheadings in the first edition of this work. Additional 

 information is treated here under the same subheadings, the page 

 number in parentheses indicating the place where the first treat- 

 ment occurred. If no number is given it is a new subtitle. 



Heterothallism (page 12) 



RecentK- heterothallism has been reported in Ascobolus ster- 

 corarius and in a recenth- described European species, Ascobolus 

 strohilinus. In 1938, Edwin M. Betts and Samuel L. Meyer 

 reported heterothallism for Ascobolus geophilus. These authors 

 after extensive studies (Am. Jour. Bot. 26: 619. 1939) conclude: 



''Ascobolus geophilus Seaver is heterothallic since the m\- 

 celium for a single spore will not develop apothecia unless crossed 

 with the mycelium from a spore of the opposite strain. 



"Four spores from a single ascus are of one strain while four 

 are of the opposite strain. 



"Segregation of sexual strains takes place at either the first 

 or second division of the zygote nucleus." 



This is as much as is known at the present of heterothallism 

 in the operculate cup-fungi. 



Spore Discharge (page 13) 



In our first edition the writer reproduced from \\\ R. Fisher 

 a photograph of a cloud of spores as the\' were being ejected from 

 the asci of Sclerotinia, one of the inoperculate discomycetes. The 

 phenomenon of spore puffing, so far as we are aware, is restricted 

 to the stomatous discomycetes, but characterizes the operculate 

 and inoperculate alike. Some time ago the writer received from 

 G. W. Goldsmith of Texas a photograph of the same phenomenon 

 in Urnula Geaster, an operculate species, which is here repro- 

 duced (Fig. 16). In this species Goldsmith states that the spores 

 are discharged with an audible sound which can be heard several 

 feet away. 



In Urnula Geaster the apothecia are at first entirely closed 

 and before the spores can be discharged it is necessary for the 



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