A "grass tree"

Found only in Australia, all 28 species of grass trees are perennial, slow-growing plants belonging to the ancient genus Xanthorrhoea. Some species produce aboveground trunks, while others do not. A grass tree’s trunk is a cylinder formed from tightly packed leaf bases... The leaves of grass trees with trunks obtain water and nutrients via aerial roots that pass down through the open core of the trunk to the ground... Bushfires blacken the trunks of grass trees, but don’t kill the plants. Like many species of eucalyptus trees, grass trees possess highly resinous leaves and exist in an intimate relationship with fire, depending on it for their survival. Flowering is stimulated by fire.