20 The North American Cup-Fungi 



dark bands which have been mentioned so frequently by the 

 writer in connection with his studies of tropical ascomycetes. 

 Whether we consider the eccentricity of the ascostome as a 

 morphological character or otherwise there is certainly a striking 

 similarity in all of the species in which it has been observed by 

 the writer, and we are inclined to regard this as one of the " ear- 

 marks " of certain genera and groups of operculate Discomycetes. 

 Just how frequently it occurs in other genera than those indicated 

 cannot be stated. 



It still remains that if the asci in those species with flat 

 apothecia have eccentrically placed ascostomes, it may be due 

 to the fact that the light rays reached the plant in an oblique 

 manner and that the ascostomes were adjusted accordingly. It 

 is impossible to follow out this line of argument since the forms 

 in which this observation has been made are tropical and we 

 have had no opportunity to experiment with them in a growing 

 condition. Even this theory would not explain the fact that the 

 ascostomes are always eccentric in some species while never so 

 in others, both of which have grown out-of-doors and been 

 subjected to the same light influences. Also it has been noted 

 that where the ascostome is eccentric the operculum usually 

 remains attached at the lower margin of the ascostome where 

 it would impede the passage of the spore in that direction. 



Our observations, up to the present time, do not seem to fit 

 in with Buller's theory, and we feel that further evidence is 

 necessary before this can be accepted as an explanation of this 

 interesting phenomenon in the species mentioned above. A 

 careful study of those forms should be made in the field. 



In all of the species in which the eccentricity of the ascostome 

 has been noted there is a great discrepancy between the size of 

 the ascostome and the spore which has passed through it (Figs. 

 9-11). Since the ascostome is intact after the spores have been 

 ejected from the ascus, there is only one conclusion — that the 

 ascostome has stretched and contracted during the process of 

 spore ejection. Another observation worthy of mention is that 

 the spores in all of these forms are strongly fusoid. From these 

 facts we might easily conclude that the small size of the asco- 

 stome, as compared with the spore, is no accident but is in some 

 way concerned with the process of spore ejection. When the 

 spore has passed half-way through the ascostome which is at 

 that time stretched to the limit, the contraction of the ascostome 



