Description: Herbaceous climbers, monoecious; stems and petioles ribbed.
Leaves alternate, biternate; leaflets toothed or lobed.
Inflorescences axillary, thyrsoid; peduncle long and with 1 or 2 pairs of circinate tendrils at apex immediately below flowers. Flowers unisexual, 4-merous. Sepals 4, paired, free. Petals 4, paired, white, scales when present oblong, crests broad. Disc 4-lobed. Stamens 6–8. Ovary 3-locular; ovule 1 per loculus; style short; stigma 3-lobed.
Capsule globose or 3-angled, membranous, inflated; seeds globose with basal aril.
Distribution and occurrence: World: 14 species, trops., especially America. Australia: 2 species (naturalized), Qld, N.S.W., N.T., W.A.
The inflated fruit are transported by water and wind, and the seeds readily germinate in disturbed ground. In some coastal districts they have become invasive weeds along stream banks and in and on the margins of disturbed rainforest.
Text by G.J. Harden
Taxon concept:
| | Key to the species | |
| 1 | Plants densely hairy; lateral petiolules 1–2 mm long; flowers 8–10 mm long | Cardiospermum grandiflorum |
| Plants finely hairy to subglabrous; lateral petiolules 2–4 mm long; flowers 3–4 mm long | Cardiospermum halicacabum |
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