Prostanthera ferricola is a species of flowering plant in the mint family (Lamiaceae) and is endemic to central Western Australia. It was first formally described by botanists Barry J. Conn and Kelly Anne Shepherd in 2007, published in the journal Nuytsia.
Taxonomy and Etymology
The species was first collected by Geoff Byrne near Meekatharra in 2003 and was initially given the informal name Prostanthera sp. Murchison (G. Byrne 239). The specific epithet ferricola is derived from the Latin ferreum (iron) and -cola (dweller), in reference to the species' habitat on banded ironstone-derived soils. The holotype specimen was collected in the Robinson Ranges on 17 August 2006 by R. Meissner and B. Bayliss (PERTH 07220618).
Description
Prostanthera ferricola is an erect, openly branched shrub that typically grows to a height of 0.3–1 m. The branchlets are cylindrical, densely hairy, and moderately glandular. The leaves are flat, ovate to narrowly ovate, 5.5–10 mm long and 1.5–2.5 mm wide, green to pale green on both surfaces, and strongly aromatic when crushed. The petiole is 0.5–1 mm long.
The flowers are arranged singly in 4 to 12 leaf axils near the ends of branchlets, each on a pedicel 0.7–1.5 mm long. The calyx has a tube 2.5–3 mm long with two lobes: the lower (abaxial) lobe is green to faintly purple-mauve (5–6 mm long), while the upper (adaxial) lobe is strongly purple-mauve (11–13 mm long). The corolla is mauve-purple, 18–20 mm long, forming a tube 15–18 mm long with two lips. The lower lip has three lobes, and the upper lip is deeply divided into two lobes. Flowering occurs from July to September.
Distribution and Habitat
This species is known from the Murchison and Gascoyne IBRA (Interim Biogeographic Regionalisation for Australia) regions of the Eremaean Botanical Province in Western Australia, specifically in areas near Cue, Meekatharra, and Wiluna. It grows infrequently in sparse Acacia aneura (mulga) shrubland on gently inclined mid to upper slopes and crests of banded ironstone, laterite, basalt, or quartz, in shallow red-brown skeletal sandy loam soils.
Conservation Status
Prostanthera ferricola is classified as "Priority Three" under the Government of Western Australia Department of Parks and Wildlife conservation codes, meaning it is poorly known and known from only a few locations but is not under imminent threat. As of its description, only six known populations existed, and the species may be vulnerable to impact from future mining activities due to its restriction to ironstone outcrops and lateritic hills.
Distinguishing Features
Prostanthera ferricola is morphologically similar to Prostanthera centralis and Prostanthera magnifica. It can be distinguished from P. centralis by its smaller leaves (5.5–10 mm long vs. 9–20(–27) mm long), strongly purple-mauve coloration of the adaxial surface of the calyx (vs. purple-green), larger corolla (18–20 mm long vs. 11–16 mm long), absence of trichomes on the dorsal surface of the connective of the anthers, and a longer pistil (20–21 mm long vs. 9–11 mm long).
