374 BOTANICAL GAZETTE [juxE 



:bie 



larger ones were obtained, the pycnidium shown in fig. j being from 

 a cankered petiole. Nearly all the diseased petioles contained the 

 covered pustules in abundance. 



In favored situations the perithecia develop also on the dead 

 leaves. Klebahn was able to see the little perithecia on the leaves 

 in the fall and found them mature about Christmas. These dates 

 differ considerably from those I observed at Ithaca. Leaves on the 

 ground were examined once or twice a week from autumn until the 

 perithecia were mature; and the first appearance of young perithecia 



January 6. They form on the inside of the leaf and are 

 until they rupture the epidermis. Generally a very small 

 three-cornered or irregular piece of the epidermis, perhaps i"''" in 

 diameter, is slightly raised; and this is the first visible evidence of 

 the perithecium. Perhaps the perithecia may have been developing 

 since early autumn, but they could not be seen. At this time they are 

 nearly globose, about 150-200 yu in diameter, and generally reach 

 nearly from epidermis to epidermis. Usually the leaf bulges out on 

 the lower side of the perithecium, so that it is really thicker than the 

 ordinary leaf. At this time the beak of the perithecium is just be- 

 ginning to form, and the wall consists of four or five layers of small, 

 black, somewhat elongated, thick-walled cells. The asci have not 

 formed yet, but the ascogenous tissue takes a different stain from the 

 surrounding contents of the perithecium. The perithecium seems to 



lie free in the leaf, and does not appear to be connected with, it by 

 hyphae. 



From this time the development is very slow. Although in January 

 the perithecia looked as if they were about ready to develop asci and 

 spores, mature spores were found first on April 21, and they were 

 on leaves that were covered and had been kept moist. This difference 

 m the time of maturing the asci as observed by Klebahn and myself 

 must be due to the different weather conditions. 



While many peritliecia were found occurring normally on the 

 fallen undisturbed leaves, the best success was obtained by placing a 

 large number of the anthracnosed leaves in wire netting and putting 

 them in a moist shady place. A large number of leaves packed close 

 together prevented drying out, which seems to be the greatest hindrance 

 to perithecial development. Also keeping the leaves close together 



