Grevillea diffusa Sieber ex Meisn.

Taxonomic Identity and Growth Habit

Grevillea diffusa Sieber ex Meisn. is most commonly a compact shrub that usually grows up to 50 cm (20 in) tall, though it sometimes grows as an erect shrub reaching 2 m (6 ft 7 in) in height.

Leaf Shape

Its leaves are elliptic, lance-shaped (with the narrower end positioned toward the base), or linear.

Leaf Morphology

The leaves measure 20–130 mm (0.79–5.12 in) long and 1–10 mm (0.039–0.394 in) wide, have silky hairs on their lower surface, and have edges that are curved downward or rolled under.

Inflorescence and Flower Color

The flowers are arranged in dome-shaped to roughly spherical groups, and their colour ranges from dark red, dark crimson to burgundy, or scarlet, depending on the subspecies.

Pistil and Style Characteristics

The pistil is usually 6–11 mm (0.24–0.43 in) long, and the style is strongly curved and more or less glabrous (hairless).

Flowering Period and Fruit Type

Flowering occurs between July and November, and the fruit that develops is a glabrous follicle.

Habitat

This species of grevillea grows in forest or woodland, and occasionally in swampy heath.

Distribution Range

It is restricted to Hawkesbury sandstone in the Sydney basin.

Subspecies Distribution

Three subspecies have distinct ranges within this area: subspecies constablei occurs south of Sydney from Waterfall to Helensburgh and near the Georges River; subspecies diffusa occurs from the lower Georges River to the Illawarra region; and subspecies filipendula occurs between Calga and Mount White, north of Sydney.