March 1906] 
Dilophospora Alopecuri 
57 
DILOPHOSPORA ALOPECURI. 
ERNST A. BESSEY. 
Last November Dr. J. J. Davis of Racine, Wisconsin, sent 
to the writer some leaves of Calamagrostis canadensis collected 
in Kenosha County of that State. Among the galls caused by 
nematodes, for which reason they were sent, were found a few 
more obscure ones of different origin. At points the leaf was 
slightly swollen, the swellings taking in the space between two 
or three ribs and being 3 to 6 mm. long and 0.2 to 0.5 mm. in 
height. They contain pycnidia in one or two rows between each 
pair of ribs. They are immersed in the leaf tissue with the 
exception of a very small area around the ostiole which is with¬ 
out a beak. Usually they are at the upper, occasionally also at 
the lower surface of the leaf. The pycnidia are carbonaceous, 
spherical, 160 to 200 //, in diameter and entirely separate, with¬ 
out a stroma, or sometimes joined together by twos or threes. 
The spores are borne apparently singly on short sporophores, 
the long axis of the spore being continuous with that of the 
sporophore. When immature (but already free in the pycnidium) 
they are hyaline and one-celled. They soon however become 
segmented into four cells, the two middle cells becoming pale 
brown, the terminal cells and appendages remaining hyaline. 
(See fig. 1.) They are cylindrical or slightly fusiform, with 
rather truncate ends from which arise two to three usually once 
or twice forking appendages, tapering towards their ends. The 
spore may be slightly constricted at the septa. Rarely the spores 
are three-celled, either with the middle cell alone or the middle 
and one end cell colored. Exclusive of appendages the spores 
measure 15 to 20 by 2 to 2.3 averaging about 17 x 2.1 /*. The 
