either of 2 distinct kinds of plants of the arum family (Araceae); genus Calla contains one species of aquatic wild plants, C. palustris, the arum lily, water arum, or wild calla; the common name calla is generally given to several species of the genus Zantedeschia, often called calla lilies; all native to South Africa; species include common florist's calla (Z. aethiopica), the golden, or yellow, calla lily (Z. elliottiana), the pink, or red, calla lily (Z. rehmannii), and the spotted, or black-throated, calla lily (Z. albomaculata)