AWARDS OF CERTIFICATES OF MERIT 1 7 



Katherine Esau, plant anatomist and histologist, for her numerous con- 

 tributions on tissue development of vascular plants and in particular 

 for her outstanding studies on the structure, development, and evolu- 

 tion of phloem. 



Alexander William Evans, who to a fruitful life as the honored master of 

 hepaticology has added a second as profitably devoted to the disen- 

 tangling of the noble genus Cladonia. 



Henry Allan Gleason, for his work on tropical and temperate floras of 

 America and for the ideas and inspiration which he has supplied to 

 the field of systematic botany. 



Thomas Henry Kearney, for his early theoretical contributions to plant 

 geography, his work in cotton breeding, his systematic studies in 

 the Malvaceae, and his part in the preparation of the "Flora of Ari- 

 zona." 



George Wannamaker Keitt, for his many contributions to plant pathology, 

 and in particular for his excellent researches on fruit-tree diseases, for 

 his leadership in plant-pathology administration, and for his patience and 

 kindness in counseling many students for whom he provided by illustra- 

 tive example the life of a true gentleman. 



Paul Jackson Kramer, for productive investigations in various branches 

 of plant physiology, and especially for significant contributions to our 

 knowledge of plant-water relations and tree physiology. 



Louis Otto Kunkel, for his researches and indefatigable efforts in experi- 

 mentation, for his wise counseling of associates and students, for experi- 

 mental techniques and publications, and for his productive studies on 

 the nature of plant viruses. 



Daniel Trembly MacDougal, for numerous contributions over many years 

 to our knowledge of various phases of plant physiology and plant ecology, 

 and especially for advances in our understanding of growth and physiology 

 of tree species. 



George Willard Martin, courageous investigator, teacher, editor, and 

 philosopher, who has brought to the elucidation of the classification of 

 the fungi field familiarity, laboratory exactness, and a critical intelligence 

 that neither claims nor acknowledges authority. 



Maximino Martinez, for his many technical and semipopular books and 

 articles on the plants of Mexico. His works have made him a recognized 

 authority on the Mexican flora and on the use of plants by man. 



Frederick Wilson Popenoe, for his efforts toward the improvement and 

 increased utilization of horticultural crops in tropical America. 



William Jacob Robbins, a physiologist whose studies have enlarged our 

 knowledge of the growth and nutrition of plants, and an administrator 

 the breadth of whose labors has notably contributed to the growth and 

 nutrition of all phases of botany. 



