62 Mendelian Inheritance and Yelloiv Rust in Wheat 



Table J. Rainfiill, Sunshine, and Mean Temperature at Cambridge from 

 January to July for the yearn 1917 to Ut20. 



Instead of looking merely at the monthly totals or averages, it appears 

 better to consider separately the more or less distinct "weather periods" 

 into which each season was naturally divided. This enables one to 

 appreciate better the effect of the weather upon the growth of the host 

 plants, and also its efiect upon the general prevalence and spread of 

 rust. The weather is thus briefly described under each season in 

 Section II. 



