140 
IOWA ACADEMY OF SCIENCES. 
tory. Professor Trelease thought it probable that the species 
came from the E aropean cultures. We are therefore inclined to 
believe with Jordan, Russell, and others that the species is not 
native in this country. 
FUNGUS DISEASES OP PLANTS AT AMES, IOWA, 1895. 
BY E. H. PAMMEL AND GEO. W. CARVER. 
In previous papers record has been made of the abundance 
of parasitic fungi for the years of 1891, 1892, 1893 and 1894.^ 
Wq hope to continue these observations for the purpose of 
making comparison. 
Obsarvations from year to year with climatic conditions 
should make it possible to say how much climate modifies the 
appearance of disease. Observations in a climate like ours are 
valuable because of the changeable conditions as to humidity 
and rainfall. Prom the nature of the diseases of plants it is 
difficult to make exact statements. We must speak in relative 
terms. In 1893 Puccinia graminis^ P. ruMgo-vera and P. coronata 
were very destructive. In 1894 these rusts were not absent, 
but they were nob destructive; in fact, scarce as compared wfith 
1893. 
In the study of diseases of plants the condition of the atmos- 
phere with reference to moisture is an important factor. The 
universally low humidity of the atmosphere in 1894, no doubt, 
largely determined the amount of rust that year. So low 
was the humidity that during the growing season dew was an 
unusual condition. 
We append table, giving rainfall, relative humidity, 7 A. M. 
temperature (ma-ximum and minimum), for the months of May, 
June, July, August and September, taken from the records 
made at Ames by Dr. J. B. Weems, Mr. W H. Heileman. 
1 L H. Pammel, Jour. Mycology, VIE, p. 95. 
Agricultural Science, VIE, p. 20. 
Proc. Iowa Academy of Science, II, p. 201-203 
