caladium, (genus Caladium), genus of about 14 species of tuberous herbaceous plants in the arum family (Araceae) native to the tropical New World. Several members of the genus, especially Caladium bicolor, are widely cultivated for their showy, fragile-looking, variably coloured leaves, and numerous cultivars have been developed. The leaves are typically heart- or arrowhead-shaped. Caladiums are nonhardy ornamentals, used as potted plants indoors and in summer outdoor plantings. They keep surprisingly well if protected from chills and wintry drafts. All parts of the plants contain calcium oxalate crystals and are considered poisonous.