This is a fairly generic term, but commonly refers to Corymbia ficifolia and all the various grafted cultivars of this genus.
The original species Corymbia ficifolia is a sturdy tree from W.A., with thick green leaves and very variable height, from as low as 2m to as tall as 12-15m. When flowering it is an absolute mass of brilliant red to orange blossom. These are followed by large woody gum nuts. They cope very well with dry windy conditions, but don’t tolerate hard frosts, waterlogging or humidity. Native birds absolutely love these trees, especially lorikeets.