Eremophila rigida, commonly known as rigid emu bush, is a species of flowering plant in the figwort family, Scrophulariaceae, and is endemic to Western Australia. It is characterized as a stiff, erect shrub with linear, rigid leaves and white to cream-coloured flowers.
Description
Eremophila rigida grows as a stiff, erect, and often spindly shrub, typically reaching a height of 0.5 to 2.5 metres (2 to 8 ft) and a similar width. The branches are often rigid and sometimes spiny, especially on older wood, and are covered with small raised points (tubercles) and sometimes also glandular hairs.
The leaves are spreading, rigid, linear to narrow-lance-shaped, and usually have a hooked, pointed tip. They are typically 6–30 millimetres (0.2–1.2 in) long and 0.8–3 millimetres (0.03–0.1 in) wide, with margins that are usually rolled under. The leaves are smooth (glabrous) and often have a glossy appearance.
The flowers are borne singly in the leaf axils on straight, rigid stalks (pedicels) 3–6 mm (0.1–0.2 in) long. The five sepals are narrow-triangular, 4–8 mm (0.2–0.3 in) long, and sometimes have glandular hairs. The petals are 10–20 mm (0.4–0.8 in) long and are white, cream, or pale yellow, sometimes with a pale purple tinge. The petals are joined at their base to form a tube. The inside of the flower tube is often hairy, especially on the lower lobe. The four stamens are enclosed within the flower tube. Flowering typically occurs from August to October. The fruit is a dry, cone-shaped to ovoid woody capsule, 4–7.5 mm (0.2–0.3 in) long, with a pointed tip.
Taxonomy and Naming
The species was first formally described by Robert Chinnock in 1986 and the description was published in Nuytsia. The specific epithet rigida is from the Latin word rigidus, meaning 'stiff' or 'rigid', referring to the plant's habit and leaves. The genus name Eremophila is derived from the Ancient Greek words erēmos (ἔρημος) meaning 'desert' and philos (φίλος) meaning 'loving', referring to the typical habitat of many species in the genus.
Distribution and Habitat
Eremophila rigida is endemic to Western Australia. It is found in the Murchison, Gascoyne, and Goldfields-Esperance regions, particularly between Cue, Yalgoo, and Menzies. It typically grows in sandy or gravelly soils, often on stony flats or ridges, within mulga (Acacia aneura) shrubland communities.
Conservation Status
This species is classified as "Not Threatened" by the Western Australian Government Department of Parks and Wildlife.