AMERICAN 
JOURNAL OF BOTANY 
Vol. IV January, 19 17 No. i 
THE INFLUENCE OF CERTAIN CLIMATIC FACTORS ON 
THE DEVELOPMENT OF ENDOTHIA PARASITICA 
(MURR.) AND. 
Neil E. Stevens 
The chestnut bHght is at present common from the northern limit 
of the chestnut, that is, southern New Hampshire and Vermont, to 
central Virginia. The area which it occupies includes the northern 
limits of growth of two native species of Endothia, Endothia gyrosa 
(Schw.) Fr. and Endothia radicalis (Schw.) De Not. It is also a 
transition region for several important plant diseases. In the southern 
portion of Jhis territory bitter rot is one of the commonest and most 
destructive diseases of apples; in the nothern portion it is a botanical 
curiosity; and pear-blight, which is so abundant in the more southerly 
portions of this area, is hardly known from the northern states of New 
England. Apple scab, on the other hand, is more important in the 
northern portion than in the southern. 
In order to gain more complete knowledge of the behavior of 
Endothia parasitica through this range and if possible to throw some 
light on the factors which limit the growth of these other fungi, the 
writer has undertaken a quantitative comparison of the growth and 
fructification of the fungus with the weather conditions, as far as data 
are available. While the work is not yet complete, enough data have 
accumulated to warrant the publication of results. This seems 
especially desirable in view of the fact that two of the stations, Wil- 
mington, Delaware, and Hartford, Connecticut, must now be aban- 
doned because of the general infection of the chestnut. 
Plan of Experiments 
Previous observations on the growth and reproduction of Endothia 
parasitica have been confined chiefly to single localities, with little 
[The Journal for December (3: 527-593) was issued January 6, 1917.] 
