Leaf anatomy and relationships of Dietes (Iridaceae)

The leaf anatomy of Dietes is described, including all 6 species. Characters support the morphological evidence that Dietes is a distinct genus and related to other Iridoideae. Certain features, notably the epidermal structure and sheath vasculature, distinguish it from other Iridaceous genera, although the sheath vasculature indicates a relationship with some New World Iridoideae. The leaf margin type is similar to that of other Old World Iridoideae. Many leaf anatomical characters in Dietes are associated with xeromorphy. Leaf anatomy supports the division of Dietes into 2 subgenera.