Margaret M. Hanes

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.

Genera 26, species ca. 650 (4 genera, 16 species in the flora): North America, Mexico, West Indies, Central America, South America, Asia, Africa, Australia; pantropical.

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).

SELECTED REFERENCE Whitlock, B. A., C. Bayer and D. A. Baum. 2001. Phylogenetic relationships and floral evolution of the Byttnerioideae (“Sterculiaceae” or Malvaceae s.l.) based on sequences of the chloroplast gene, ndhF. Syst. Bot. 26: 420–437.