Malvaceae subfam. Byttnerioideae
Outlines Bot., 821, 1119. 1835.
Herbs, subshrubs, shrubs [trees]. Leaf blades usually unlobed, rarely lobed (Hermannia), margins serrate, dentate, or entire. Inflorescences axillary, terminal, or leaf-opposed, usually antisepalous or absent (Hermannia and Waltheria); gynoecium syncarpous. Fruits capsules or schizocarps, dehiscence loculicidal or septicidal. Seeds (1–)5–10, usually glabrous.
North America, Mexico, West Indies, Central America, South America, Asia, Africa, Australia, pantropical.
Genera 26, species ca. 650 (4 genera, 16 species in the flora).
Byttnerioideae comprise five tribes previously ascribed to the family Sterculiaceae (B. A. Whitlock et al. 2001). It is sister to Grewioideae; together they represent the earliest branching taxa in the family (C. Bayer et al. 1999; R. Nyffeler et al. 2005).