PEDALIACEAE (sesame family)

About 13 genera, about 60 species, native to the Old World, most diverse in tropical regions; a few species introduced widely in the New World.

The Pedaliaceae traditionally have been divided into three distinctive subfamilies that are often treated as separate families (Thieret, 1977; Manning, 1991). Subfamily Pedalioideae is the largest and most morphologically diverse of the groups and includes trees, shrubs, and herbs. The genus Proboscidea and 3 or 4 other New World genera were included in the Martynioideae, differing from Pedalioideae primarily in their inflorescence structure, ovary construction and placentation, and pollen morphology. The third subfamily, Trapelloideae, contains only the Asian genus, Trapella Oliv., with 1 or 2 species of prostrate aquatics having modified flowers with 2 stamens and an inferior ovary. Recent molecular studies have provided support for the view that these three groups are each more closely related to other families in the order Lamiales than to each other. Pedaliaceae in the strict sense appear allied with the Acanthaceae (Olmstead et al., 2001). The Martyniaceae apparently are related to the Verbenaceae (Gutierrez, 2008). Relationships of Trapella within the Lamiales have not been fully resolved, but some authors have suggested affinities with the Plantaginaceae (see Ihlenfeldt [2004] and Mabberley [2008] for brief reviews).