Malvaceae subfam. Byttnerioideae


Outlines Bot., 821, 1119. 1835.

Treatment appears in FNA Volume 6. Treatment on page 202. Mentioned on page 188, 197.

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).


1 Anthers 3-thecate; staminodes present; sepals distinct or connate. Ayenia
1 Anthers 2-thecate; staminodes usually absent; sepals connate > 2
2 Ovules 4–14 per locule. Hermannia
2 Ovules 2 per locule > 3
3 Ovaries 5-locular. Melochia
3 Ovaries 1-locular. Waltheria