Family Sapindaceae > Subfamily Sapindoideae.

There are 15 or 16 species of herbacous balloon vines with some cultivated as garden ornamentals.
Cardiospermum halicacabum and C. grandiflora are now weeds in Australia.

The two are similar.
C. grandiflorum is a larger plant with dense hairs on young stems while C. halicacabum stems are hairless.
C. grandilforum flowers are 6 mm or longer; C. halicacabum flowers are up to 4 mm.
C. grandiflorum has pointed capsules 5 cm or longer; in C. halicacabum they are rounded and up to 3 cm.