Acacia drewiana


Acacia drewiana is a species of flowering plant in the family Fabaceae and is endemic to the south-west of Western Australia. It is a subshrub with hairy branchlets, bipinnate leaves, spherical heads of golden yellow flowers and leathery, narrowly oblong, crusty pods.

Description

Acacia drewiana is a subshrub that typically grows to a height of, commonly to about and has winding branchlets with soft hairs. The leaves are sessile bipinnate, long, continuous with and extending downwards from the branchlet. Each leaf has 2 to 4 pairs of pinnae, each with 2 to 6 pairs of narrowly oblong pinnules long, wide, with the edges rolled down or curved under. The flowers are borne in a spherical head in axils on a hairy peduncle long, each head large with 22 to 35 densely arranged, golden yellow flowers. Flowering occurs from April to July, and the pods are leathery, narrowly oblong, long, wide and crusty with shaggy and soft hairs.

Taxonomy

Acacia drewiana was first formally described in 1917 by William Vincent Fitzgerald in the Journal and Proceedings of the Royal Society of New South Wales from specimens he collected near Cannington.
In 1975, Bruce Maslin described two subspecies of A. drewiana, and the names are accepted by the Australian Plant Census:Acacia drewiana W.Fitzg. subsp. drewiana has the tips of the pinna stalks flattened and turned down, the pinnules mostly long.Acacia drewiana subsp. minor Maslin the tips of the pinnacle stalks straight or turned down but not flattened, the pinnules long.

Distribution and habitat

Acacia drewiana subsp. drewiana grows in sandy loam, sand, gravel and clay in heath and open jarrah or wandoo woodland, sometimes in winter-wet depressions, from near Eneabba to Mundijong in the Geraldton Sandplains, Jarrah Forest and Swan Coastal Plain bioregions of south-western Western Australia.Acacia drewiana subsp. minor has a disjunct distribution, growing in similar habitats to the autonym, at Wongan Hills and near Newdegate in the Avon Wheatbelt and Mallee bioregions.

Conservation status

Acacia drewiana subsp. drewiana is listed as "not threatened", but subsp. minor is listed as "Priority Two" by the Government of Western Australia Department of Biodiversity, Conservation and Attractions, meaning that it is poorly known and from one or a few locations.