The geranium bronze or brun des pélargoniums in French (Cacyreus marshalli) is a butterfly in the family Lycaenidae. The wingspan is 15–23 mm for males and 18–27 mm for females. Adults are on wing year round in warmer areas, but usually from August to May in South Africa. At higher altitudes adults are on wing in December and January. It is brown with a fine black edge interlaced with white and a very thin tail. The underside is grey-brown with dark bands. The caterpillar feeds on cultivated Pelargonium geraniums, as well as on species of the related Geranium genus.