(glē´sen) , 1882-1975, American botanist, plant geographer, and plant ecologist. His floristic studies of North American vegetation led to his
“individualistic concept of the plant community,”
which views each species as functioning independently within the plant community, a concept that has gained favor in recent years. He co-authored two important books with Arthur Cronquist , The Natural Geography of Plants (1964) and the Manual of Vascular Plants of the Northeastern United States and Adjacent Canada (1963, repr. 1991). He also wrote The New Britton and Brown Illustrated Flora of the Northeastern United States and Adjacent Canada (1952).
