176 Robinson. — Notes on the Genus Taphrina. 
down to 1 ix and less, while in Taphrina caerulescens they 
are oblong or cylindrical, and usually less than 2 //, in 
diameter. As the size of the spores in these polysporic asci 
depends upon the extent of the subdivision of the original 
eight spores, a process which is very probably influenced by 
external circumstances, the diameter of such polyspores, so 
variable in the same species, can hardly be considered a 
character of sufficient definiteness to warrant the separation 
of forms which differ in no other particular. 
In closing I wish to express my sincere thanks to Dr. W. G. 
Farlow, who very kindly furnished me with the material for 
studying this group, and aided my work with many valuable 
suggestions. 
Cambridge, Mass., U. S.A. 
