Family STERCULIACEAE
Description: Trees or shrubs, mostly with stellate indumentum.
Leaves alternate, simple or rarely palmately compound; stipules present or absent.
Inflorescences axillary, leaf-opposed or terminal, mostly many-flowered cymes or panicles, rarely flowers solitary or paired. Flowers actinomorphic, bisexual or unisexual and then plants monoecious or dioecious. Sepals usually 5, either basally fused or calyx tubular and mostly 5-lobed, valvate, persistent in fruit. Petals 5, often minute and scale-like or absent. Stamens 5–30, either free and often alternating with staminodes, or subsessile on an androgynophore; anthers 2-locular, dehiscing longitudinally by slits or rarely by terminal pores. Ovary superior, sometimes on a gynophore; carpels 3–5, free or united, ovules 2–many, style simple or lobed, or rarely styles free.
Fruit a follicle or loculicidal capsule, rarely a samara.
Distribution and occurrence: World: 65 genera, c. 1100 species, mainly tropical & subtropical regions. Australia: 21 genera, c. 160 species, all States, widespread, especially in SW W.A.
Some species of Heritiera are used locally for timber. Cocoa is extracted from the seeds of Theobroma cacao L. A few species are cultivated as ornamentals, especially species of Brachychiton, Dombeya, Lasiopetalum and Thomasia.
Text by G. J. Harden
Taxon concept:
| | Key to the family STERCULIACEAE | |
| 1 | Trees or shrubs more than 4 m high | 2 |
| 2 | Leaves palmately 3–9-lobed; fruit a samara | Heritiera |
| 2* | Leaves simple, margins entire to toothed, or lobed; fruit a capsule or follicle | 3 |
| 3 | Leaves with petiole more than 20 mm long; margins not toothed; lamina either 3–7-lobed, or unlobed and glabrous or sparsely hairy on lower surface; fruit a follicle, more than 30 mm long | 4 |
| 4 | Leaves either 3–7-lobed, or entire and glabrous below; follicles stalked, hairy and yellowish brown inside, after opening seeds embedded along base | Brachychiton |
| 4* | Leaves entire and very sparsely stellate-pubescent on lower surface (lens needed); follicles sessile, glabrous and orange inside, after opening seeds attached along upper margins | Sterculia |
| 3* | Leaves with petiole less than 20 mm long; margins mostly irregularly toothed and lamina densely hairy on lower surface, mostly unlobed, sometimes obscurely lobed in juvenile shoots; fruit a bristly capsule less than 20 mm long | 5 |
| 5 | Capsules 15–20 mm diam., bristly, bristles covered with soft stellate hairs, carpels not separating in fruiting stage | Commersonia |
| 5* | Capsules c. 10 mm diam., tomentose but without bristles, carpels separating in fruit | Seringia |
| 1* | Shrubs less than 4 m high (mostly less than 2 m high) or rarely herbs | 6 |
| 6 | Herbs; stems prostrate to 30 cm long; hairs glandular and stellate | Gilesia |
| 6* | Shrubs; stems mostly erect, sometimes prostrate; hairs stellate but not glandular | 7 |
| 7 | Epicalyx of 3 persistent subulate bracteoles; petals yellow, c. 10 mm long | Melhania |
| 7* | Epicalyx absent; petals not yellow, less than 10 mm long | 8 |
| 8 | Calyx enlarged in fruit, papery, blue to purplish or white, sparsely or densely pubescent | Keraudrenia |
| 8* | Calyx not markedly enlarged in fruit, whitish green to pink to rusty-coloured, tomentose at least on the outside | 9 |
| 9 | Capsules covered with bristles 2–5 mm long; calyx not prominent in fruit, not enclosing and shorter than the capsule | Rulingia |
| 9* | Capsules without bristles; calyx prominent in fruit, longer than and mostly enclosing the capsule | 10 |
| 10 | Calyx lobes 10–15 mm long, linear-subulate, striate; capsule c. 10 mm diam.; peduncle with 1 or 2 fruits | Hannafordia |
| 10* | Calyx lobes usually less than 10 mm long, more or less ovate, rarely oblong; capsule usually less than 5 mm diam.; peduncle mostly with many fruits, rarely 1 or 2 | Lasiopetalum |
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