Infection experiments with Puccinia helianthi Schw

"Sunflower seedlings were grown in four or five inch flower pots. The seed was obtained from Henry A. Dreer, of Philadelphia, J.M. Thorburn and Co., of New York, Rev. J.M. Bates, of Red Cloud, Nebraska, E. Bartholemew, of Stockton, Kansas, B. O. Longyear, of Fort Collins, Colorado, and local forms were collected around Columbia, Missouri. When the seedlings had four to six leaves they were inoculated with the uredospores. The uredospores for the first culture were obtained from G. w. Freiberg of the St. Louis Botanical Garden. The teleutospores used were collected on the wild varieties growing in the vicinity of Columbia." -- Page 32.