Canna lilies (Canna: Cannaceae) are popular garden ornamentals throughout warm temperate regions,especially in the eastern US and Europe. Over 1000 named cultivars have been generated by hybridization and cultivation over the past 200 years. One species, Canna edulis, is grown in tropical regions around the world as an "arrowroot" starch source for both humans and as animal fodder. Many general plant books recognize approximately 50 species and new neotropical species continue to be described based on characters such as leaf, staminode, and rhizome size and shape. Morphological research suggests the number of species is grossly inflated. Nuclear ITS and chloroplast rpl16 intron DNA sequence data for 22 plants representing 7 broadly-defined species were collected. Molecular data confirm the recognition of a limited number of species including a broadly defined Canna indica. Morphological variation of the C. indica specimens sampled include leaf color (green versus purple) and surface (glabrous versus glaucous), flower color (all red, yellow with small reddish spots, or a range of colors between these two extremes), and plant height. The important crop plant C. edulis falls within the broad morphological definition of C. indica. DNA data also group our sample of C. edulis with all other C. indica representatives. The closest relative of C. indica is the semi-aquatic species C. glauca. Other species which warrant specific recognition based on this study include: C. tuerkheimii, C. jaegeriana, C. paniculata, C. iridiflora, and C. flaccida.

Key words: Canna, Cannaceae, ITS, phylogeny, rpl16 intron