Lewis & Short

caltha, ae, f. (calthum, i, n., Prud. Cath. 5, 114) [cf. Gr. χάλκανθος], a strongsmelling yellow flower, prob. our pot marigold: Calendula officinalis, Linn.; Plin. 21, 6, 15, § 28; Verg. E. 2, 50; Col. 10, 97; 10, 310.