10 



alesce from the older stages. 



The outline of the spots in the later stages became 

 definite, usually round (Plate III). The color was then almost 

 black (Plate II, No. V).. Outside of this black portion was a 

 brilliant red. This was brightest at the border and radiated over 

 a large part of the apple, sometimes covering half of it, becoming 

 less and less bright, and usually ending in a mottling or striping. 



The spot varies from two millimeters to about three centi- 

 meters in diameter (Table I). The progress of the fungus is very 

 slow. Two apples were marked on the twelfth of November, and on 

 the twelfth of March there was not more than 2 mm. of growth on 

 the blackened part of one, the reddened portion apparently remain- 

 ing the same, and no change at all on the other. The growth pro- 

 bably takes place in the orchard as the fruit develops. 



Structure in Cross Section 



The fungus in the deepest spot observed penetrated only 

 about 3 mm. deep. The average was from 1 to 2 mm. Plate I, 

 Figs. 1, 2, 3, 4, 5, give an idea of the appearance of the spot 

 in cross section. Fig. 1 shows the flattening effect of the fun- 

 gus. In Fig. 2 the area where the epidermis is darkest and thick- 

 est is more sunken. This is probably where the infection began, 

 as the f ruit did not develop evenly. Fig. 3 shows only the mar- 

 gins sunken. In Fig. 4 the thic): vein in the fruit prevented the 

 fungus developing at that point. A very deep infection is shown 

 in Fig, 5, This was from one of the darkest colored spots. 



The growth of the mycelium into the tissue caused the 



