Prostanthera grylloana

Prostanthera grylloana is an erect shrub that typically grows to a height of 0.3–1.5 m (1 ft 0 in–4 ft 11 in) and has densely hairy branchlets. The leaves are spatula-shaped, 3–5 mm (0.12–0.20 in) long and about 2 mm (0.079 in) wide on a petiole up to about 1 mm (0.039 in) long. Both the petiole and leaf blade have a longitudinal groove so that the two sides of the leaves almost touch. The flowers are arranged singly in leaf axils, each flower on a pedicel 1–1.5 mm (0.039–0.059 in) long. The sepals are 4–6 mm (0.16–0.24 in) long and form a tube 4–4.5 mm (0.16–0.18 in) long with two more or less triangular lobes about 2 mm (0.079 in) long and 3–4 mm (0.12–0.16 in) long. The petals are red to dull medium mauve-pink, 15–20 mm (0.59–0.79 in) and fused to form a tube 10–14 mm (0.39–0.55 in) long with two lips. The lower lip has three lobes, the centre lobe more or less triangular, 5 mm (0.20 in) long and 2–3 mm (0.079–0.118 in) wide, the side lobes about 2.5 mm (0.098 in) long wide. The upper lip is 3.5–4 mm (0.14–0.16 in) long and 4 mm (0.16 in) wide with a central notch about 1 mm (0.039 in) deep. Flowering occurs in February, May or from September to December.[2][3]

Prostanthera grylloana was first formally described in 1876 by Ferdinand von Mueller in his book Fragmenta phytographiae Australiae from specimens collected "in the desert around Ularing" by Jess Young.[4][5] The specific epithet (grylloana) honours the actress Adelaide Ristori, the wife of the marchese Giuliano Capranica del Grillo.[5][6]

This mintbush grows on granite outcrops and ridges and on stony hills and undulating plains in the Avon Wheatbelt, Coolgardie, Mallee and Murchison biographic regions of Western Australia.[2][3]

Prostanthera grylloana is classified as "not threatened" by the Western Australian Government Department of Parks and Wildlife.[2]