Plant of the Month — December 2012
Monotoca aristata A.R.Chapman
Monotoca aristata grows as moderately dense, erect bushy dioecious shrubs to 0.8(-1.5) m tall, and up to 0.7 m wide, with light yellow-green alternate, spreading to horizontal, linear-lanceolate aristate leaves to 15.5 mm long and 2.5 mm wide. It grows in patches of open banksia heath on well-drained, dark grey, stony quartzite sand or on flats in white sand over laterite and flowers from May to early August, with the peak in June. The species was recently described in our journal Nuytsia from which much of this text is transcribed.
Monotoca aristata has no close allies in the genus, differing from all other taxa in the genus in possessing thick, strongly ribbed, linear-lanceolate leaves with five conspicuous parallel veins on the abaxial face, and also by the presence of short, dense puberulence on the interior of the corolla lobes. It is currently known from a small number of populations in the extreme west of the Fitzgerald River National Park and around the locality of Wellstead within remnant vegetation, including a small population in Mettlers Lake Nature Reserve. This species has been assigned Priority Two status under the Department of Environment and Conservation (DEC) Conservation Codes for Western Australian Flora.
Collections of unidentified material from near Mt Maxwell in the Fitzgerald River National Park in the 1960s and 1970s were provisionally identified as a new taxon belonging within Monotoca. Later evidence, both morphological and molecular strongly supported the grouping of this new taxon with the eastern species and is the sole Western Australian representative of the genus. The endemic Australian genus Monotoca R.Br. now consists of eleven currently recognised taxa, ten distributed throughout eastern Australia including Tasmania. Three western species, previously considered to belong to that genus have recently been segregated into the new genus Dielsiodoxa Albr. and placed, together with the monotypic Oligarrhena R.Br., into the tribe Oligarrheneae.
Monotoca is derived from the Greek — mono ‘one’ and toca ‘cell’, referring to the single-celled ovary; and aristata from the Latin — arista referring to the hard, straight point terminating the leaf. The genus now belongs to the family Ericaceae.
Photo: A. Spooner
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