Plant of the Month: Feb. 2018

Olearia arckaringensis. Photo: P.J. Lang

A few months ago, State Herbarium botanist Peter Lang and SA Seed Conservation Centre‘s Dan Duval, were part of a field trip to Arckaringa Station. One of the main aims of the trip was to survey populations of Olearia arckaringensis P.J.Lang, the State Herbarium of South Australia‘s Plant of the Month for February 2018.

Olearia arckaringensis, flower. Photo: A.C. Robinson.

The plant was first discovered in 2000 in gullies of breakaways in an isolated pocket of Arckaringa Station by DEWNR scientists Rob Brandle and Peter Lang. The daisy was recognised to be a new species and described in 2008 by Peter in the Journal of the Adelaide Botanic Gardens (895kb PDF). A further two populations were found in 2011 along the same breakaway system on the neighbouring property, Evelyn Downs. In 2016, O. arckaringensis was listed as Endangered under the federal EPBC Act (80kb PDF).

The recent survey discovered several new population of the species. The search took more than 100 hours and covered more than 100 km of breakaway country. The survey team counted and mapped well over 2000 Arckaringa daisy plants and confirmed that the species is rare with quite specific habitat requirements. It was mainly restricted to breakaway sites that had a softer more powdery underlying substrate and were situated in less exposed areas.

Voucher specimens of Olearia arckaringensis and other plants were collected for the State Herbarium and the Seed Conservation Centre. Such collections are vital to build plant knowledge and improve scientists’ ability to accurately describe and identify different species, whilst the stored seeds are a valuable insure against species extinction.

Olearia arckaringensis, old shrub with woody base. Photo: R. Brandle.

The plant is a small, compact perennial shrub, usually to around 30 cm tall, with grey-green leaves and light violet-lavender flowers (occasionally white) borne on long stalks. It rapidly develops a thick woody base from which it can regrow.

More information can be found in DEWNR’s newsletter The Weekly and SA Arid Land’s news release.