First report of a well-established Ambrosia (Asteraceae) to the nonnative African flora.

Ambrosia confertiflora a perennial herb native to North America and Caribbean has been recorded as a new alien to the vascular flora of African continent, second report to the Mediterranean area. In Tunisia, A. confertiflora is reported naturalized from few localities in the centre of the country where the species has established small and extended populations in surrounding ruderal disturbed habitats. A short morphological description as well as its distribution and habitat in Tunisia with color photos are presented. Moreover, a key to the Ambrosia species in the African continent is here firstly provided. [ABSTRACT FROM AUTHOR]