Jacksonia sternbergiana Hügel

Growth Form and Size

Jacksonia sternbergiana is an erect or weeping shrub or small tree, which typically reaches 1.5–5 m (4 ft 11 in – 16 ft 5 in) in height and 1–3 m (3 ft 3 in – 9 ft 10 in) in width.

Branch Characteristics

It has dull green branches; its terminal branches are 4–92 mm (0.16–3.62 in) long, 1–2 mm (0.039–0.079 in) wide, and sharply pointed.

Leaf Structure

The leaves of this species are reduced to broadly egg-shaped, pale brown scales that measure 1.0–3.3 mm (0.039–0.130 in) long and 0.7–2.2 mm (0.028–0.087 in) wide.

Flower Arrangement and Pedicel

Its flowers are scattered along the branches, each growing from a 5.5–8.3 mm (0.22–0.33 in) long pedicel.

Bracteole Features

Lance-shaped bracteoles 0.6–1.2 mm (0.024–0.047 in) long are attached to the middle of each pedicel.

Floral Tube and Sepals

The floral tube is 1.3–1.4 mm (0.051–0.055 in) long. The sepals are membranous, with lobes that are 7.3–9.7 mm (0.29–0.38 in) long and 1.3–2.3 mm (0.051–0.091 in) wide.

Flower Coloration

The flowers are yellow-orange with red markings.

Petal Dimensions

The standard petal is 8.9–10 mm (0.35–0.39 in) long, the wing petals are 7.7–10 mm (0.30–0.39 in) long, and the keel petal is 7.2–9 mm (0.28–0.35 in) long.

Stamen Characteristics

The stamens have white filaments with red ends, and the filaments measure 6–11.7 mm (0.24–0.46 in) long.

Flowering Period and Fruit

Flowering occurs year-round, and the fruit is a woody, hairy pod that is 10–15.5 mm (0.39–0.61 in) long and 4.5–6.0 mm (0.18–0.24 in) wide.

Distribution Range

This species of Jacksonia is widespread between Northampton and Green Range, within the Avon Wheatbelt, Geraldton Sandplains, Jarrah Forest, Mallee and Swan Coastal Plain bioregions of south-western Western Australia.

Ecological Role

This plant serves as food for the larvae of several butterfly species, including the turquoise jewel, fringed heath-blue, and long-tailed pea-blue.