Banksia integrifolia integrifolia

Description

Banksia integrifolia is a highly variable species. It is most often encountered as a tree up to 25 metres (80 ft) in height, but in sheltered locations it can reach 35 metres (110 ft). In more exposed areas it may grow as a small, gnarled tree, reaching to no more than about 5 metres (15 ft), and in highly exposed positions, such as on exposed coastal headlands, it may even be reduced to a small shrub. It usually has a single stout trunk, which is often twisted and gnarled, with the rough grey bark characteristic of Banksia. The leaves are dark green with a white underside, and occur in whorls of three to five. Adult leaves have entire margins; George specifies their dimensions as 4 to 20 centimetres (2–8 in) long and 6 to 35 millimetres (0.2–1.4 in) wide,\but The Banksia Atlas warns that "Atlas contributors found great variability in these measurements with specimens often falling outside the varietal limits specified by George (1981) or being intermediate between two varieties." Juvenile leaves have dentate margins with a few short teeth, and are generally larger than adult leaves. Flowers occur in Banksia's characteristic "flower spike", an inflorescence made up of several hundred flowers densely packed in a spiral around a woody axis. This is roughly cylindrical, 10 to 12 centimetres (4–5 in) high and five centimetres (2 in) wide. Flowers are usually pale yellow to yellow, but may be greenish or pinkish in bud. Each individual flower consists of a tubular perianth made up of four united tepals, and one long wiry style. Characteristic of the taxonomic section in which it is placed, the styles are straight rather than hooked. The style ends are initially trapped inside the upper perianth parts, but break free at anthesis. This process starts with the flowers at the bottom of the inflorescence, sweeping up the spike at an unusually high rate of between 96 and 390 flowers per 24 hours. The flower spikes are not as prominent as in some other Banksia species, as they arise from two- to three-year-old nodes nested within the foliage. After flowering, old flower parts wither and fall away over a period of several months, revealing the "cone", a woody axis embedded with many small follicles. The follicles are initially greenish and downy, but gradually fade to dark grey. Each follicle contains one or sometimes two seeds, separated by a thin wooden separator. The seed itself is black, 6 to 10 millimetres (0.2–0.4 in) long with a feathery black 'wing' 10 to 20 millimetres (0.4–0.8 in) long.