Belgian catholic priest and botanist (1825–1871).
Henri Eugène Lucien Gaëtan Coemans (30 October 1825, Brussels – 8 January 1871, Ghent) was a Belgian Catholic priest and botanist. In 1848 he obtained his ordination, later serving as a curate in Ghent (from 1853). In 1864 he became a member of the Académie royale des Sciences et Belles-Lettres de Bruxelles, followed by a professorship at the Catholic University of Leuven in 1866. From 1868 to 1871 he was director of a Franciscan convent in Ghent. As a taxonomist he identified the genus Fittonia (family Acanthaceae). The genus Coemansia is named in his honor.