Juniper grevillea (Grevillea juniperina)

Description

Grevillea juniperina, commonly known as juniper- or juniper-leaf grevillea or prickly spider-flower, is a plant of the family Proteaceae native to eastern New South Wales and south-eastern Queensland in Australia. Scottish botanist Robert Brown described the species in 1810, and seven subspecies are recognised. One subspecies, G. j. juniperina, is restricted to Western Sydney and environs and is threatened by loss of habitat and housing development. A small prickly leaved shrub between 0.2 and 3 m (8 in to 10 ft) high, G. juniperina grows generally on clay-based or alluvial soils in eucalypt woodland. The flower heads, known as inflorescences, appear from winter to early summer and are red, orange or yellow. Birds visit and pollinate the flowers. Grevillea juniperina plants are killed by bushfire, regenerating afterwards from seed. Grevillea juniperina adapts readily to cultivation and has been important in horticulture as it is the parent of many popular garden hybrids. Grevillea juniperina has a spreading or erect habit (growth form) and it grows to between 0.2 and 3 m (8 in to 10 ft) in height. The branchlets are thick and sturdy. The prickly leaves are generally stiff, and are 0.5–3.5 cm (1⁄4–1 3⁄8 in) long and 0.5–6 mm (1⁄32–1⁄4 in) wide. They are crowded along the stems. Flowering occurs throughout the year, peaking between mid winter and early summer, though varies between the different subspecies. Subspecies allojohnsonii flowers from September to February, subspecies trinervis flowers from August to December, and subspecies juniperina, amphitricha, sulphurea, villosa and fortis flower in August and September. The spider-flower arrangement of the inflorescence has several individual flowers emerging from a central rounded flower head—reminiscent of the legs of a spider. The flowers are red, pink, orange, yellow or greenish, and are mostly terminal—arising on the ends of stems—though they occasionally arise from axillary buds. They are 2.5–3.5 cm (1–1 3⁄8 in) long. The perianth is finely furred on the outside, while the pistil is smooth; it is 1.5–2.7 cm (5⁄8–1 1⁄8 in) long. Flowering is followed by the development of seed pods, each capsule is 10–18 mm (3⁄8–3⁄4 in) long, and releases one or two seeds when ripe. The narrow oval seed is 7.5–12 mm (1⁄4–1⁄2 in) and 2.2–3.3 mm (1⁄16–1⁄8 in) wide, with a swelling at the apex and a short wing. Both surfaces are covered with tiny hairs.