Prostanthera verticillaris

Prostanthera verticillaris is a species of flowering plant in the family Lamiaceae and is endemic to a restricted area of Western Australia. It is a spreading shrub with whorled, egg-shaped to elliptic leaves and white to purplish-blue flowers.

Description
Prostanthera verticillaris is a spreading, openly-branched shrub that typically grows to a height of 0.5–2 m and has hairy branches. The leaves are arranged in whorls of three or four, more or less glabrous, egg-shaped to elliptic, 9.5–11 mm long, 4–6 mm wide and sessile or on a petiole up to 1 mm long. The flowers are borne on groups of six to eight near the ends of branches, each flower on a pedicel about 2 mm long. The sepals form a tube about 3.5 mm long with two lobes, the lower lobe about 2 mm long and the upper lobe 4–4.5 mm long. The petals are white to purplish-blue, 9–12 mm long and form a tube with two lips, the lower centre lobe spatula-shaped, 5.3–6.8 mm long and the side lobes about 2.5 mm long. The upper lip is egg-shaped, about 4 mm long and wide with a central notch about 1.2 mm deep. Flowering occurs from September to October.

Taxonomy
Prostanthera verticillaris was first formally described in 1988 by Barry Conn in the journal Nuytsia from specimens collected by Kenneth Newbey north-east of Albany in 1967.

Distribution and habitat
This mintbush grows on granite outcrops and is only known from the type location in the Esperance Plains biogeographic regions of Western Australia.

Conservation status
Prostanthera verticillaris is classified as "Priority One" by the Government of Western Australia Department of Parks and Wildlife, meaning that it is known from only one or a few locations which are potentially at risk.