INFLUENCE OF CERTAIN CLIMATIC FACTORS 
19 
perithecia and ascospores by the middle of November. He refers to 
the perithecial stromata developing "abundantly in the autumn 
around the old pycnidia." 
Rogers and Gravatt (10, p. 45) report that in their inoculations 
at Leesburg, Va., made on July 21 and August 16, 1912, pycnidia with 
spore horns were developed by October 6. Although the cankers 
were examined in March and again in August, 1914, no perithecia 
were found. 
That unfavorable conditions may delay for a long time and perhaps 
entirely prevent the production of ascospores was first brought to the 
writer's attention by inoculations of Endothia parasitica on chestnut 
sprouts near Washington, D. C. These inoculations were made in 
July, 1913, and produced abundant pycnidia within two weeks. 
Sections of the stromata made in September, 191 3, showed numerous 
fundaments of perithecia. The inoculations were conveniently 
located and as they were from the first material sent from China by 
Meyer were frequently examined. The cankers continued to grow 
normally and in most cases girdled the sprouts and formed numerous 
stromata with abundant pycnospores and fundaments of perithecia. 
Up to December, 1914, however, when the sprouts were destroyed by 
fire, no ascospores had developed. 
Field Observations 
When this work was begun it was expected that ascospores would 
be produced in the fall as had been the case in the work of Anderson 
and Babcock and of Rankin and other investigators. Actually, 
however, at none of the stations was a single canker in the entire series 
of inoculations found which had produced ascospores or even mature 
appearing perithecia during the season for 1914. In 1915, however, 
quite different climatic conditions existed. Perithecia and mature 
ascospores were found in abundance not only on cankers arising from 
inoculations made in 1914 but from those made in May, 1915. The 
problem then became not so much a comparison of the fructification 
at different localities as a comparison of the fructification during 
different seasons at the same locality. 
Table VIII gives the results of observations at the various localities 
on the development of perithecia and mature ascospores. It is evident 
that no perithecia were produced during the season of 1 914 at any of 
the localities. Observations made December, 1914, at stations as 
