Orange banksia (Banksia prionotes)

Description

Banksia prionotes, commonly known as acorn banksia or orange banksia, is a species of shrub or tree of the genus Banksia in the family Proteaceae. It is native to the southwest of Western Australia and can reach up to 10 m (33 ft) in height. It can be much smaller in more exposed areas or in the north of its range. This species has serrated, dull green leaves and large, bright flower spikes, initially white before opening to a bright orange. Its common name arises from the partly opened inflorescence, which is shaped like an acorn. The tree is a popular garden plant and also of importance to the cut flower industry. Banksia prionotes grows as a tree up to 10 m (30 ft) high in southern parts of its distribution, but in northern parts it is usually a shorter tree or spreading shrub, reaching about 4 m (13 ft) in height; it diminishes in size as the climate becomes warmer and drier further north. It has thin, mottled grey, smooth or grooved bark, and tomentose young stems. The alternate dull green leaves are 15–27 cm (6–11 in) long, and 1–2 centimetres (1⁄3–2⁄3 in) wide, with toothed leaf margins made up of triangular lobes, and often a wavy surface. Flowers occur in a typical Banksia flower spike, an inflorescence made up of hundreds of small individual flowers, or florets, densely packed around a cylindrical axis. B. prionotes has cream-coloured flowers with a bright orange limb that is not revealed until the flower fully opens. Known as anthesis, this process sweeps through the inflorescence from bottom to top over a period of days, creating the effect of a cream inflorescence that progressively turns bright orange. The old flower parts fall away after flowering finishes, revealing the axis, which may bear up to 60 embedded follicles. Oval or oblong in shape and initially covered in fine hairs, these follicles are from 14 to 20 mm (1⁄2 to 3⁄4 in) long and 6–11 mm (1⁄4–3⁄8 in) wide, and protrude 3–6 mm (1⁄8–1⁄4 in) from the cone. Inside, they bear two seeds separated by a brownish woody seed separator. The matte blackish seeds are wedge-shaped (cuneate) and measure 8–10 mm (3⁄8–3⁄8 in) long by 5–6 mm (1⁄4–1⁄4 in) wide with a membranous 'wing'.