is a messy genus
of about 1000 species of herbaceous forb
s, and subshrub
s (and at least one tree) in the family Asteraceae
, and is the largest genus in the tribe Vernonieae
. Because of the wide range of species lumped
into this genus, some botanists have suggested breaking it up; in these systems, the name Vernonia
may be kept to refer to one of the smaller genera.
The Vernonieae are characterized by alternating cauline leaves, homogamous heads, and flat to convex receptacles. The Vernonia are characterized by heads that are not covered by small leaves, and with apparent scale-, bristle-, or feather-like calyx.
Popular members of the genus Vernonia include ironweed, and the edible species including bitterleaf, ewuro, ndole, and onugbu. Bitterleaf is also a popular medicinal herb for treating diabetes, fever, and headaches; other species also have medicinal uses. Some species of ironweed are used to make vernonia oil, which has various industrial uses.
The genus is named for English botanist William Vernon; the name Vernon, in turn, comes from a Gaul word meaning 'place of the Alder tree'. (Alder trees are unrelated to the Vernonia, belonging to the genus Alnus).
eFloras: Asteraceae Martinov tribe Vernonieae