waldjumi

Jacksonia sericea is a spreading to prostrate shrub that typically grows up to 0.3–1 m (1 ft 0 in – 3 ft 3 in) high and 1–2 m (3 ft 3 in – 6 ft 7 in) wide. It has greyish-green branches, the end branches 2.2–25 mm (0.087–0.984 in) long, 0.3–0.8 mm (0.012–0.031 in) wide and mostly sharply-pointed. Its leaves are reduced to narrowly egg-shaped, pale brown scales with toothed edges, 0.9–1.8 mm (0.035–0.071 in) long and 0.4–1.1 mm (0.016–0.043 in) wide. The flowers are scattered along the branches on a pedicel 1.7–2.8 mm (0.067–0.110 in) long, with narrowly egg-shaped bracteoles 0.7–1.4 mm (0.028–0.055 in) long on the middle or near the top of the pedicels. The floral tube is 1.2–1.6 mm (0.047–0.063 in) long and the sepals are membranous, with lobes 7.5–8.8 mm (0.30–0.35 in) long and 0.9–1.7 mm (0.035–0.067 in) wide. The standard petal is orange with red markings, 4.9–7 mm (0.19–0.28 in) long, the wings are orange without markings, 5.2–7.6 mm (0.20–0.30 in) long, and the keel is orange or red, 5.5–5.9 mm (0.22–0.23 in) long. The stamens have white filaments with pink ends and 5.1–5.8 mm (0.20–0.23 in) long. Flowering occurs from October to January, and the fruit is a woody, densely hairy pod 5.5–5.7 mm (0.22–0.22 in) long and 4–5 mm (0.16–0.20 in) wide.

This species of Jacksonia grows in sandy soil over limestone, and is found in Perth suburbs between Wanneroo and Mandurah in the Swan Coastal Plain bioregion of south-western Western Australia.