Henslow, John Stevens (henz'lō) [key], 1796–1861, English botanist. He was professor of mineralogy (1822–27) and of botany (1827–61) at Cambridge Univ. Henslow was a teacher and friend of Charles Darwin, whom he recommended as naturalist to the Beagle expedition. He wrote on scientific farming and also A Catalogue of British Plants (1829) and Dictionary of Botanical Terms (1857).