Balga is a common and widespread grasstree. It has a bumpy and deviating trunk, made of layers of flattened leaf bases, and which grows slowly at only 1.5 cm per year. The trunk can grow to over 3 m, as can its spear. The upper two thirds of the spear (known as the flowering spike) produces thousands of white flowers in spring, which subsequently give way to seed capsules, containing shiny black seeds.
Ref: “Leaf and branch: trees and tall shrubs of Perth” by Robert Powell. Published by the Western Australian Department of Environment and Conservation, 2009.