Vlll SOURCES OF ILLUSTRATIONS, 



41, 42, 44, 45, 4G, 47, 48, 110, and 150, from the Md. 

 Agr. Exp. Sta., through Prof. A. L. Qiiaintance, these 

 havmg heen first used by the author iu The Farmers' 

 Review; Figs. Go, 132, and 133, from the Ky. Agr. Exp. 

 Sta., through Prof. H. Carman; Fig. 125, from the Fhi. 

 Agr. Exp. Sta., through Prof. H. A. Gossard; Figs. 54, 

 55, 56, 57, 58, 63, 70, 96, 98, 101, and 103, from the 

 Ohio Agr. Exp. Sta., through Prof, F. M. Webster; Fig. 

 49, from the Minn. Agr. Exp. Sta., through Director 

 W. M. Liggett; Figs. 12 and 95, from the DeL Coll, Agr. 

 Exp. Sta.; Fig. 151, from the Peninsula Horticultural 

 Society, through Prof. Wesley Webb. 



Figs. 19, 20, 21, 6(j, 138, 139, 140, 141, 144, and 147 

 were loaned by the author. Figs. 13, 14, 15, 16, 17, 18, 

 23, 26, 27, 99, 115, 145, 149, 152, and 153 were copied 

 from prints. Figs. 1, 4, 5, 6, 8, and 10, and Figs. 2, 3, 

 22, 86, 87, and 100 and frontispiece are original from 

 photos by the author, the photos of the latter numbers 

 being loaned by the Del. Coll. Agr. Exp. Sta. 



