[Editor's Note: This week we feature a ScienceThen that first aired last year.]
Wednesday is the birthday of Augustin Pyramus de Candolle, a French plant taxonomist born in 1778. Candolle introduced key principles into plant classification. He adopted the scheme that plants are divided into three main groups--acotyledons, monocotyledons, and dicotyledons--based on the number of embryonic seed leaves that appear when a shoot begins to grow, or germinate. Candolle argued that the structure and form of organisms, rather than their physiology, should be the basis for classifying species. According to this principle, Candolle proposed that taxonomists look for patterns of symmetry, especially of floral organs, to determine the relatedness of plant groups. Candolle created the Botanical Conservatory and Botanical Garden in Montpellier, France, and left a 17-volume descriptive account of flowering plants and conifers.
[SOURCE: TREVOR I. WILLIAMS, ED., A BIOGRAPHICAL DICTIONARY OF SCIENTISTS (JOHN WILEY & SONS, ED. 3, NEW YORK, 1982).]