Fall Flowers. The firewheel tree (Stenocarpus sinuatus) takes its name from the configuration and colour of the inflorescences in which the small flowers have a wheel-like arrangement. It is one of Australia's most spectacular trees. S.sinuatus occurs in nature as a tree to about 30 metres but it is usually smaller in cultivation, particularly in cooler areas. The dark, glossy green leaves may be entire or lobed and up to 450 mm long. The conspicuous flower clusters are seen in summer through to autumn.