xxii DEDICATION: CARY A. MITCHELL
complete and thoughtful person: scientist, teacher, mentor, and friend,
with devotion to community, church, and most especially, to family.
Modest and caring, Cary and Letty have raised three children, Carlton,
Lesley, and Collin, who are each pursuing successful careers in their
own right.
ROBERTJ. JOLY
Department of Horticulture and Landscape Architecture
Purdue University
West Lafayette, IN, USA