Ageratum
ageratum
(ˌædʒəˈreɪtəm
) noun
any tropical American plant of the genus Ageratum, such as A. houstonianum and A. conyzoides, which have thick clusters of purplish-blue flowers
[C16: New Latin, via Latin from Greek agēraton that which does not age, from a-1 + gērat-, stem of gēras old age; the flowers of the plant remain vivid for a long time]
