This name is a synonym of Ageratum conyzoides (L.) L..
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 1BC42625-4002-4646-8396-5D9D8C73288B) with original publication details: Encycl. Suppl. 1: 242. 1810. 242 1810.
This name record (from TICA) was not included in version 1 of The Plant List. It is possible the same name was included from a different data source, to check this you can search for Ageratum hirsutum in version 1 of The Plant List.