1921] MILES—LEAF SPOTS OF ELM 179 
contained some spores apparently almost mature as early as the 
middle of February. On only one leaf, however, were any of the 
perithecia at that time mature enough to expel spores. This leaf 
was on the shelf of the wire cage, which was placed directly against 
the south wall of the greenhouse, and was exposed both to the 
direct rays of the sun and also to the heat rays radiated from the 
cement wall. In most cases at that time the asci were somewhat 
more developed than when observed in the fall, but the spores 
were not yet differentiated. The normal development during the 
winter, therefore, seemed to be very slow. In leaves which were 
in especially damp situations, as those buried in the soil or those 
in intimate contact with the soil under a cover of other leaves, 
most of the perithecia were found to be dead and disintegrated. 
In general, it seemed that leaves neither in too exposed nor too 
moist a situation, as for instance those toward the middle of a 
pile of leaves, showed the greatest development of the fungus late 
in winter and early in the spring. 
CONIDIAL STAGE 
In every specimen examined in which the ascigerous stage of 
Gnomonia ulmea occurred, I have found constantly associated 
with it an imperfect or conidial form. This stage was found present 
from early spring until late fall on every leaf collected, and also 
on all exsiccati material examined, even the Schweinitzian type 
specimen previously mentioned. I have examined all available 
published exsiccati specimens of Gnomonia ulmea, as well as more 
than 100 other specimens obtained for purposes of comparison 
from various educational institutions and private individuals, 
including several from the Royal Botanical Gardens, Kew, England, 
and the herbarium of the University of Geneva, Geneva, Swit- 
zerland. The published exsiccati specimens examined are as 
follows: RAVENEL Fung. Amer. Exsic. no. 752; RAVENEL Fung. 
Carol., Fasc. IT, no. 63; Erxis and EverHart Fung. Col. nos. 239, 
2928, and 3422; SEyMouR and Earte Econ. Fung. nos. 155a and 
155b; Exzis N. Am. Fung. no. 1347; BRENCKLE Fung. Dakotensis 
no. 329; RABENHORST-WINTER Fung. Eur. nos. 3661a and 3661b; 
and von THUMEN Myc. Univ. no, 1155. 
