Webster's research included study of the diverse family Euphorbiaceae (spurges), on which he produced many papers, and he lectured on plant systematics, biogeography, and the ecology of pollination.
Webster's career as a plant systematist was distinguished by the field research he undertook in remote tropical areas.
Born in Ada, Oklahoma on 14 April 1927, his parents were Irena Lois Heard and Grady Webster, a newspaper publisher.
[1] An interest in the diverse Euphorbiaceae plant family inspired his field research, travelling to remote tropical and subtropical regions in Africa, South and Central America, the Caribbean, Australasia, and Europe.
He led an expedition to study the flora of a region known as the Maquipucuna Reserve in the Andes, publishing surveys and a book on the remarkable species diversity of its cloud forests.