fleabane, in botany: A genus of plants belonging to the class of Syngenesia, and to the order of Polygaminia aquilis; and in the natural system ranging under the 49th order, Compositae. The receptacle is villous, and the pappus plumy: the calyx is monophyllous, turbinate, and half divided into seven segments. There are only three species known; the camphoratus, glaber, and ericoides.