General Features 207 



the OpercLilates and the Inoperculates. Now a thu-d must be 

 added. 



Earh- in the writer's work on the discomycetes it was noted 

 that Patellaria atrata, one of the xerophytic species commonh- 

 collected in the west, seemed to be an exception to the general 

 rule, so far as the discharge of its spores is concerned, in that no 

 pore or ascostome had ever been observed through which the 

 spores could have escaped. Instead a third of the ascus was 

 broken off and these remained in the field as detached thimbles. 



It remained for Miss Ellys Butler to determine the method of 

 spore discharge in Patellaria (Lecanidion) and its allies. It was 

 discovered by her in fresh material collected b\' the writer in 

 Bermuda that Patellaria possesses a double ascus, a character that 

 had been observed in some of the pyrenomycetes but never before 

 in the discomycetes. Under proper conditions the inner ascus, 

 which is termed b\- her the endoascus, elongates and extends 

 through the outer ascus, termed by her the ectoascus, about 

 one-third of its length carrying with it the ascospores which are 

 discharged one by one not directly through the ascostome of the 

 ectoascus but through the end of the endoascus. 



The spores are ejected from the endoascus in the same manner 

 described by the writer for certain of the operculate cup-fungi, 

 in which the ascostome is much smaller than the spore. In 

 Patellaria, however, the process takes place in "slow motion" 

 so that it can be easily observed. The process has been de- 

 scribed by Miss Butler as follows: "The first four spores were 

 shot out in rapid succession, the last ones more slowly, so that 

 the process could be followed easily (Fig. 23). A spore pushed 

 forward to the apex and, stretching the contracted pore, slowly 

 squeezed through the opening to the point of maximum width 

 of the spore and then was shot out quickly and forcefully. Thus 

 the shape of the spore seems to play an important part in its 

 discharge. Seaver described this process of stretching and con- 

 tracting in the operculates, but he was unable to follow the 

 discharge closely as there then was no pause between spore ejec- 

 tions and the motion was too rapid." 



One point has not yet been cleared up. It has not yet been 

 determined how the endoascus makes its exit through the ecto- 

 ascus. Does it pass through a definite opening at the end of the 

 ascus, or does it push off the end of the ectoascus in the form 

 of a thimble? If the latter were true some of the thimbles should 



