Bui. 213, Bureau of Plant Industry, U. S. Dept. of Agriculture. 



Plate XVI. 



(1) Chestnut on daisy ; less than natural size ; inoculated Nov. 1 3, 1908. Time: 4 months 



10 days. 



(2) a, Alfalfa on alfalfa; inoculated Sept. 7, 1909. Time: 2 months 25 days, b, Ordinary 



nitrogen-fixing nodules of alfalfa, introduced for comparison. 



