New YORK AGRICULTURAL EXPERIMENT STATION. 227 
Unlike the Ascochyta leaf spot, this disease attacks chiefly green 
leaves in the upper part of the plant. The spots are circular, one 
to three millimeters in diameter and usually light brown with a 
narrow border of dark brown. (See Plate XXVI, fig. 4.) Each spot 
bears several light brown pycnidia visible on both surfaces of the 
leaf. The pycnidia closely resemble those of the Ascochyta 
described above except that they are somewhat larger, usually 180 
in diameter. In water the spores escape through the ostiolum in a 
gelatinous rope-like mass. The spores are hyaline, straight or 
-lightly curved, rounded at the ends and measure 14-28 x 4 + the 
most common size being 20-21 x 4 v4, In most cases the spores 
appear non-septate. However, septate spores occur abundantly in 
the more mature pycnidia which may be distinguished by their 
darker color and especially by the whitening of the leaf tissue at the 
center of the spot on which they are seated. The number of septa 
varies from one to four, being usually three. Frequently, slight 
constrictions occur at the septa. 
We have been unable to find any account of an alfalfa disease 
like this one. However, there is a very similar leaf spot of sweet 
clover, Melilotus alba, caused by Stagonospora carpathica Bauml. 
the description” of which agrees quite closely with the characters 
possessed by our fungus. We should not hesitate to refer the 
alfalfa fungus to this species but for the fact that numerous sweet 
clover plants growing among the affected alfalfa plants were en- 
tirely free from the disease. 
This leaf spot is readily distinguished from the Ascochyta leaf 
spot and Cercospora leaf spot (next to be described) by the dark 
brown border surrounding the spots. 
CERCOSPORA LEAF SPOT. 
(Cercospora medicagims E. & E.) 
A Cercospora on alfalfa foliage was found but once, viz., on June 
12, 1908. Only occasional leaves were affected. The Cercospora 
spots occurred chiefly on green leaves about half way up the plant. 
They were mostly circular with indefinite outline, smoke-colored or 
nearly black, 1.5 to 2.5 millimeters in diameter and visible on both 
Surfaces of the leaf. (See Plate XX VI, fig. 3.) The spores 
measured 40-135 x 4 » and were 6- to 15-septate. Both in gross 
appearance and in microscopic characters our specimens agree 
Pieaceardo (86, 10:334). 
