ACKNOWLEDGMENTS 



The following individuals, companies, and institutions have 

 supplied the illustrations referred to by the figure numbers opposite 

 to their names: 



Arkansas Experiment Station, Fayetteville, Ark 126, 127 



Prof. W. G. Brierley, University of Minnesota, St. Paul 53 



California Experiment Station, Berkeley 105, 106, 111, 112 



Country Gentleman, Philadelphia 97, 108, 125 



Prof. A. W. Cowell, State College, Pa 20 



Garden Magazine, Garden City, N. Y 27a, 59, 70, 71, 103, 107 



N. R, Graves, Rochester, N. Y. 



1, 2, 5, 8, 21, 26, 61, 66, 81, 85, 90, 93, 101, 109, 110, 113, 115 



House and Garden, New York City 28, 96, 122, 131 



Idaho Experiment Station, Moscow 32, 35 



Indiana Experiment Station 9, 10 



R. M. Kellogg Co., Three Rivers, Mich 124 



Kelly Bros., Dansville, N. Y 24 



Kentucky Experiment Station, Lexington 99, 100, 102 



E. T. Kirk, State College, Pa 



37, 43, 49, 54 to 57, 87, 92, 101, 116, 117, 129, 130 



E. T. Kirk (developing and printing author's photos) 



11, 13, 14, 15, 18, 19, 31, 33, 34, 44 



Missouri Experiment Station, Columbia 16, 25 



North Carolina Experiment Station, Raleigh 89 



Ohio Experiment Station, Wooster 45-47 



Pennsylvania State College Horticultural Department, State College 



Pa 67, 68 



United States Department of Agriculture, Washington, D. C. 



17, 58, 72-80, 86, 123 



Van Dusen Nurseries, Geneva, N. Y 60, 62, 63, 64, 65, 114 



West Virginia Experiment Station, Blacksburg 83, 84, 95, 118, 119 



Wisconsin Experiment Station, Madison 27 



