Arctotheca Vaill.
Arctotheca is a genus with five species, all originally restricted to South Africa (mainly the Cape region). At least two species have spread beyond their native range as environmental weeds: Arctotheca calendula and A. populifolia (Bergius) T. Norlindh. The former, commonly known as Cape weed, is fast spreading in parts of southern Europe and has been recorded as a casual alien in Belgium.
Literature:
Adamson R.S. & Salter T.M. (1950) Flora of the Cape Peninsula. Juta & Co., Cape Town: xix + 889 p.
Goldblatt P. & Manning J. (2000) Cape plants : A conspectus of the Cape flora of South Africa. Missouri Botanical Garden Press, St. Louis, Missouri: 743 p.
Hilliard O.M. (1977) Compositae in Natal. University of Natal Press, Pietermaritzburg: 659 p.
McKenzie R.J., Muller E.M., Skinner A.K.W., Karis P.O. & Barker N.P. (2006) Phylogenetic relationships and generic delimitation in subtribe Arctotidinae (Asteraceae: Arctotideae) inferred by DNA sequence data from ITS and five chloroplast regions. Am. J. Bot. 93(8): 1222-1235.