Malvaceae subfam. Sterculioideae
Outlines Bot., 821, 1119. 1835.
Trees [shrubs]. Leaf blades unlobed or lobed, ultimate margins entire or serrate. Inflorescences axillary or terminal, paniculate [racemose]. Flowers usually functionally unisexual, rarely bisexual; epicalyx absent; sepals persistent or late-deciduous, (4–)5(–8), connate, petaloid, nectaries usually at base on adaxial surface, sometimes absent; petals absent; androgynophore present; stamens [4–]10–30, basally connate; anthers 2-thecate; staminodes absent; gynoecium apocarpous. Fruits follicles [nuts]. Seeds 1–22[–144], glabrous or hairy.
Introduced; Asia, Pacific Islands, Australia, pantropical.
Genera ca. 12, species ca. 400 (2 genera, 2 species in the flora).
Genera in Sterculioideae historically have been recognized as a morphological group (H. W. Schott and S. L. Endlicher 1832; A. L. Takhtajan 1997; P. Wilkie et al. 2006) due to the presence of mostly unisexual flowers with androgynophores and without petals. Individually, these elements are found throughout Malvaceae; their combination is exclusive to Sterculioideae. Generic relationships within Sterculioideae are complicated. Firmiana is closely related to Hildegardia Schott & Endlicher and, as currently circumscribed, is not monophyletic (Wilkie et al.).