THE FUNGUS CAUSING THE ROT. 29 



more, and, being embedded in a gelatinous matrix, they adhere to 

 any object with which they come in contact. As the spores mature 

 the protophism surrounding them becomes denser and forms a sort of 

 secondary membrane (PL III, fig. 14, r). The ascus has a character- 

 istic apex which suggests that of Hypocopra, as described by Zopf *^ 

 and also by Griffiths,^^ though in Acanthorhynchus it does not turn 

 blue upon the application of iodin and does not show the peculiar 

 thickenings observed by Zopf. The mass of protoplasm surrounding 

 the spores reaches to the apex of the ascus and is attached there. In 

 the case of some asci from which the spores have been discharged a 

 small caplike portion remains, which suggests that the ascus may rup- 

 ture about the apex. In other cases, however, the spores seem to have 

 been discharged through the apical pore or the ascus has been split 

 longitudinally from the apical pore. It has been impossible to differ- 

 entiate or to positively distinguish a secondary membrane about the 

 mass of gelatinous jorotoplasm in which the spores are embedded, 

 but the manner in Avliich it holds together would signify that there 

 may be an outer layer functioning as a secondary membrane. 



Cultures of the fungus. — Cultures of this fungus were first obtained 

 from mycelium found in the interior of rotten lierries. These cul- 

 tures were made by transplanting the mycelium as described in the 

 case of Guignardia imccinii. Perfect perithecia and asci have been 

 produced in forty different cultures made from diseased berries. 

 In a number of instances a mycelium apparently identical with that 

 of Acanthorhynchus has appeared, but no perithecia were ever 

 formed. The fungus grows and reproduces most readily on corn 

 meal, corn meal agar, and cranberry agar and corn meal. A few 

 mature perithecia have been formed on steamed sweet potato cylin- 

 ders. The fresh ascospores sometimes germinate quickly in moist 

 air and produce appressoria in a few hours. In most cases in which 

 spores have been observed to germinate, appressoria have been 

 formed. The spores very rarely germinate in culture media. 

 They germinate in damp air or water on glass and also on 

 cranberry leaves. In pure cultures the fungus first forms a branched 

 white mycelium, which spreads concentrically from the point of 

 origin, forming a rather close white layer, which continues to 

 spread until the whole surface of the culture medium is covered. 

 Soon the mycelium begins to assume a dirty, ochraceous color, which 

 becomes quite uniform and is soon followed by the appearance of the 

 dark perithecia of the fungus. These, when full grown, give a dark 

 cast to the surface as they become uniformly distributed throughout 

 the yellowish layer. As in case of other ascogenous forms whose 

 natural mode of growth is within the tissues of their host, the peri- 

 thecia in cultures are more or less covered with fungous hyphae, with 



110 



