Dieffenbachia , commonly known as dumb cane or leopard lily, is a genus of tropical flowering plants in the family Araceae. It is native to the New World Tropics from Mexico and the West Indies south to Argentina. Some species are widely cultivated as ornamental plants, especially as houseplants, and have become naturalized on a few tropical islands.

Dieffenbachia is a perennial herbaceous plant with straight stem, simple and alternate leaves containing white spots and flecks, making it attractive as indoor foliage. Species in this genus are popular as houseplants because of their tolerance of shade. The English names, dumb cane and mother-in-law's tongue (also used for Sansevieria species) refer to the poisoning effect of raphides, which can cause temporary inability to speak. Dieffenbachia was named by Heinrich Wilhelm Schott, director of the Botanical Gardens in Vienna, to honor his head gardener Joseph Dieffenbach (1796–1863).