348 Bulletin 73. 



shoots is the same as the one in the leaves is not known. A few 

 shoots on one tree by the roadside near Crowbar Point on the 

 west shore of Cayuga Lake were found by me on June 28, 1894, 

 They were enlarged for some distance from the ends and the 

 greater diameter of the hypertrophied shoot was some distance 

 from the end. They were also curved to one side by torsion, 

 usually nearly at a right angle, but in one case the torsion had 

 continued until the shoot made an entire revolution and the end 

 then pointed in nearly the same direction as the main part of the 

 shoot. This one is reproduced in fig. 18, Plate VIII. Some of 

 the leaves of these same shoots were deformed by a species of 

 Exoascus. Somewhat similar distortions of the leaves were found 

 along the Dry den road between Aetna and Varna, July 6 and 28. 

 A few only were found on a very few of the shrubs which also 

 possessed the cecidomid galls. None of the shoots here were 

 deformed. An examination of the tissues of the shoots and 

 and leaves thus deformed showed the presence of the mycelium 

 of an Exoascus. 



Fig. 84 represents the intercellular mycelium in a twig, and fig. 

 80 the mycelium and very early stage of the formation of the 

 hymenium in a petiole of a very young leaf in a bud of the same. 



Prunus demissa Walp. 

 Exoascus varhisf Atkinson. 



Among other specimens communicated to me by Prof. Pammel 

 was one from the Herb, of Prof. Wm. Trelease, collected in Ute 

 Pass, Colorado, on the leaves of Pru7ius demissa Walp. The 

 affected spots appear to have been arched and slightly folded, 

 forming rather shallow open pockets, much like those which I 

 have here observed on the leaves of Prunus virginiana , to which 

 P. demissa is closely related. In the specimens observed the asci 

 were developed on the upper surface of the leaves forming a 

 whitish coating to the spots. Some of the asci are illustrated in 

 fig- 33- Without more material and fuller observations I do not 

 care to definitely locate the species. It is marked Taphrina de- 

 formans. It seems to me that the proportion existing between the 

 length of the stalk cells and the asci is different from that in the 

 specimens on the peach, and agrees more closely in that respect 



