Brooks: The Fruit Spot of apples 451 



course (plate 30, figure 3). In no case was the fungus defi- 

 nitely traced from one of these pockets to another. Careful search 

 was made for hyphae that had penetrated the cell-walls but none 

 were found. In some cases they seemed at first sight to be within 

 the cells, but a closer observation showed that the cells had col- 

 lapsed and that the hyphae were in the cavity they had left. The 

 mycelium in the pockets of the host tissue was coarse, septate, 

 thick-walled, and brown, such as was often obtained in the 

 stromatic layers of cultures. From these coarse threads arose 

 fine hyaline apparently non-septate ones which spread out into the 

 apple tissue. Chlamydospores were common on the coarse 

 hyphae but conidia were never found within the apple tissue. 



As was previously mentioned, spots that had become much 

 enlarged, sunken, and browned sometimes had a minute elevation 

 in the center (page 43 3). Sections through these showed that the 

 epidermis had been raised in this manner through the agency of 

 a fungous mass beneath. A dense stroma from 60 to 100 p. in 

 diameter and about 50 ,a deep, occupied a pocket beneath the 

 lenticel or stroma. Equally dense layers extended laterally from 

 this between the host cells for a radial distance of 100 to 400/*. 

 The stromatic mass was hyaline or of a yellowish tint, and was 

 composed of closely woven, septate, thick- walled hyphae that had 

 a dla meter of about 5 //. In spots in which the fungus had not 

 yet broken through the epidermis a somewhat conical fungous 

 ma ss that seemed to be composed of fine granular hyaline threads 

 arose fr °m the upper surface of the stroma (plate 32, figure 2). 



n oIder stages this had been forced through the epidermis as a 

 a yer of erect hyaline sporophores (plate 32, figure 3). The 

 sporophores were extremely thin-walled, usually septate, and either 



inched or unbranched. The conidia were produced in a manner 



plate 



35, figure 2). They were hyaline, from one- to five-celled, 2 to 

 2-5 P ln diameter, 15 to 70 // long, often larger at the basal than 

 le free en d, and were variously curved and contorted. 



Th 



Identity of the fungus 



v . e descriptions of the previous pages together with the 

 an °us fig Ures to which references have been given furnish 



