 Panicles of creamy-yellow flowers with red markings appear from September to November in the species' native range. These arise from axillary buds on end branches. Each panicle contains 10 – 30 flowers and is 3 – 8 centimetres (1.2 – 3.1 in) long, and each flower is 0.5 – 1 centimetre (0.2 – 0.4 in) long and 1.3 – 1.8 centimetres (0.5 – 0.7 in) wide. The length of the lobes of the perianth is more than half the perianth diameter. Like all Brachychiton species, B. rupestris is monoecious — each plant has distinct male and female flowers. Male flowers have 15 stamens, with pale yellow anthers, while female flowers have cream or white stigmas surrounded by rudimentary stellate (star-shaped) carpels, which sit atop the ovaries.
