Plant of the Month — November 2012

Tetratheca spenceri R.Butcher & Cockerton

Find out more about Tetratheca spenceri R.Butcher & Cockerton

Tetratheca spenceri is currently known from a single population on a laterite outcrop south-east of Coolgardie and is of conservation significance. Five rare, short-range endemic Tetratheca taxa are already known from Banded Iron Formation ranges in the Coolgardie bioregion. Tetratheca spenceri can be distinguished from all other species of Tetratheca in the region by its combination of straight, finely wrinkled, glaucous stems, alternate, appressed, narrowly deltoid scale-leaves, moderately long peduncles bearing long, glandular hairs, uniformly pink petals, two ovules per locule, which are crowded together near the apex of the septum, and narrowly obovate, glabrous fruit.

Tetratheca spenceri was discovered serendipitously by Southern Cross resident, gold prospector, and regional flora and fauna survey co-ordinator Charlie Spencer, while exploring breakaway country south of Coolgardie in November 2011. It grows as a clumped subshrub with small, appressed scale-leaves on its mature stems. These leaves fall early, leaving only small remnant bases, so that the plants are ‘leafless’ in appearance. Flowers occur from November to February. The species was recently described in our journal Nuytsia by Ryonen Butcher and Geoff Cockerton, from which much of this text is transcribed. The paper also includes a number of detailed colour plates and a key to the ‘leafless’ Tetratheca taxa of WA.

Tetratheca is derived from the Greek — tetra ‘four’ and theca ‘box’, referring to the four cells of the anthers. The genus now belongs to the family Elaeocarpaceae. The taxon is named for Paul Geoffrey (Charlie) Spencer who discovered this species while exploring the unique landscapes of the Coolgardie bioregion and the common names ‘Spencer’s Tetratheca’ and ‘Charlie’s Gold’ have been proposed. In thanking Charlie for having such a keen eye and marvellous enthusiasm for the unique vegetation and landscapes of the Yilgarn, the authors of the recent paper describing T. spenceri write — “without the Charlies of this world, botanical gold such as this would lie undiscovered”.

Photo: D. Warden

Find out more about Tetratheca spenceri R.Butcher & Cockerton

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