Brooks : The Fruit Spot of apples 453 



its sporophore. From these facts and from the unlikeness of the 

 hosts the writer is not inclined to consider the two fungi identical. 



Cylindrosp 



Pomi. 



Cylindrosporium Pomi Brooks, sp. nov. — Acervulis pallidis, 



subeffusis, primo subepidermicis, dein erumpenti-liberis. Conidiis 

 hyalinis, granulosis, filiformibus, rectis vel flexuosis, 15-80 // X 

 2-25 /i. In fructu Mali Mali (L.) Britton, in America Boreali. 



Summary and conclusions 



1. The writer considers that the facts and indications given 

 justify the conclusion that the Fruit Spot of New Hampshire apples 

 is due to a parasitic fungus, Cylindrosporium Pomi Brooks. 



2. This fungus gains entrance to the apple in July or early 

 August, a time when the stomata are being torn open and the pro- 

 tecting layers of the lenticels are not yet formed, a season when 

 the metabolism of the apple is extremely great and the transpira- 

 tion stream necessarily large. 



3- The fungus makes its way into the intercellular spaces be- 

 neath the stomata and between the cells of the surface zone, obtain- 

 >ng the substances necessary for its existence from the transpira- 

 tion stream and from the rapidly maturing host cells. 



4- If the fruit is attacked before the cells have lost their power 

 to respond to external stimuli the fungus is soon partially sur- 

 rounded by a layer of brown, thick-walled cells which may serve 

 * a barrier to its further nutrition. In such cases the results are 

 not altogether unlike those obtained from a minute puncture or an 

 ms ect sting. 



5- If, however, the fungus attacks the host cells when they 

 are nearly mature, it finds conditions more favorable for its devel- 

 opment, because the cell sap furnishes more satisfactory food ma- 

 enal and the cells are at the same time unable to respond to its 

 Presence. The result is a more vigorous development of the fungus 



a ra P ld browning and drying of the host tissue. 



6 - The chlamydospores and sclerotial masses of the fungus are 

 Probable agencies in carrying the disease through the winter. 



7- Conidia have not been found on the host in the fall. They 



the 



Probabl 



y develop from sclerotia and pycnidia in the following 



