Banksia dentata (Banksia dentata)

Description

The tropical banksia is generally a small tree which grows to around 4 m (13 ft) or sometimes 7 m (23 ft) tall, with a rough stocky trunk, spreading crown, and crooked branches.The dark grey bark is not flaky but tesselated in texture and appearance. Initially covered in reddish hair that wears away, branchlets become smooth and grey with age. The large green leaves are scattered along the stems, and more crowded at the branchlet tips. They are 9–22 cm (3.5–8.7 in) long and 2–9 cm (0.79–3.54 in) wide, obovate in shape with mucronate tips. The dentate (toothed) margins are lined irregularly with 0.1–1.3 cm (0.039–0.512 in) long teeth, separated by u-shaped sinuses. The leaves are undulate (wavy) with white undersurfaces, the midrib raised underneath and depressed above. The cylindrical yellow inflorescences (flower spikes), arise from one- to three-year-old branches. Appearing between November and May, they are 10 to 13 cm (3.9 to 5.1 in) high and 5 to 10 cm (2.0 to 3.9 in) wide. Newly opened flower spikes smell like corn.All flower parts are pale yellow; the perianth is 2.5–3.2 cm (0.98–1.26 in) long, including a 0.5 cm (0.20 in) long limb. After anthesis, the pistil is 3.1–4.6 cm (1.2–1.8 in) long. Flower parts soon fall off ageing spikes, which develop into irregular-cylindrical infructescences. The oval follicles are 1.5–2 cm (0.59–0.79 in) long, 0.4–0.8 cm (0.16–0.31 in) high and 0.5–0.8 cm (0.20–0.31 in) wide. Pale green and furry when young, they become smooth and pale brown with age. The follicles open spontaneously with maturity. They contain two seeds each, between which lies a woody dark brown separator of similar shape to the seeds. Measuring 1.8–2.1 cm (0.7–0.8 in) in length, the seed is obovate, and composed of a dark brown 1.1–1.4 cm (0.4–0.6 in) wide membranous 'wing' and obovate seed proper which measures 1.0–1.2 cm (0.4–0.5 in) long by 0.5–0.8 cm (0.2–0.3 in) wide. The seed surface can be smooth or covered in tiny ridges.The bright green cotyledons are obovate, measuring 1.6–1.9 cm (0.63–0.75 in) long by 0.8–1.1 cm (0.31–0.43 in) wide. At the base of each are two pointed auricles around 1.5 mm long. The cotyledons arise from a 3–4 mm high smooth hypocotyl that is 1–1.5 mm in diameter. The subsequent seedling leaves are opposite initially, arising 3–4 mm above the cotyledons. Each is roughly linear in shape, measuring 2.5–2.7 cm (0.98–1.06 in) long and 0.4–0.5 cm (0.16–0.20 in) wide, with two to three serrations ("teeth") on the upper quarter to third of the leaf margin's length. The leaf undersurface is covered with white hair. Successive leaves become more obovate and are 3–7 cm (1.2–2.8 in) long and 0.8–1.2 cm (0.31–0.47 in) wide, with dentate margins and mucronate tips. Seedling stems are hairy.