The calla lily, Zantedeschia aethiopica, is not a true lily but an arum of southern Africa, its striking white bloom formed of a single furled bract, the spathe, wrapped around a golden central spike. Introduced to Europe as an ornamental, its pure white sculptural form made it, like the true lily, an emblem of purity and of the resurrection, and it became a favourite flower of Easter. Its cool, elegant simplicity carried a symbolism of chastity and of transcendent beauty.
A plain caution belongs with the plant: like many arums, the calla lily contains calcium oxalate crystals in its sap and tissue, which cause a sharp burning irritation to the mouth and throat if chewed, mildly toxic to both people and pets, a fact worth stating plainly beside its reputation as a flower of purity. In the twentieth century the flower gained an entirely new cultural life through art, above all in the paintings of the Mexican muralist Diego Rivera, who painted calla lily vendors repeatedly as a symbol of Mexican identity and labour, and in the large-scale, close-cropped calla lily paintings of the American artist Georgia O'Keeffe, which read the flower's sculptural white form in an idiom entirely independent of its older Christian symbolism.
Sources Plants of the World OnlineRoyal Botanic Gardens, Kew with Encyclopaedia Britannica (online academic reference)Encyclopaedia Britannica editors