Acacia bifaria

General Plant Info

Acacia bifaria also known as the "Clay Wattle" is a small shrub, 0.3-0.8 m high, to 2 m wide, with yellow flowers. A prostrate or semi-prostrate, commonly domed shrub, endemic to Australia, it grows in undulating plains, roadsides, low-lying areas, in scrub, mallee communities and woodland between Ravensthorpe and Fitzgerald River.

Flowers August to Oct or Dec

Mostly distributed outside protected areas in a highly fragmented habitat due to clearing for agriculture. The extent of occurrence warrants this species a listing of Endangered (EOO ~3,700 km2).

Changes in fire regimes, increased salinity, mining activities and grazing pressure are threatening processes to this habitat. Furthermore, despite some populations known from the Fitzgerald National Park, there are concerns over the devastating effects that the pathogen Phytophthora cinnamomi might have on the vegetation of the area if the spread of this disease is not contained. If the current management measures to contain the spread are not successful there is a high risk that some populations will become extinct. It is recommended that monitoring of the habitat status, threats and pathogen are continued

Closely related to Acacia glaucoptera which is most readily distinguished by its glaucous phyllodes, which have a dense tuft of white hairs in their axils (minutely resin-haired in Acacia bifaria), and heads 30–80-flowered. Also, in Acacia glaucoptera the free portion of the phyllode is generally longer, broader and commonly protracted to an acute or acuminate apex.

Acacia bifaria has a more restricted distribution than A. glaucoptera and although both are common around Ravensthorpe it is not known if they are ever sympatric.

The phyllodes on some specimens from around Ravensthorpe are occasionally undulate as in the Bremer Bay variant of A. glaucoptera .

Geographic distribution

Endemic to Australia, Acacia bifaria is only known from approximately six localities in Mallee of Western Australia from Ravensthorpe to the Fitzgerald River (c. 30 km east of Jerramungup) in south-western Western Australia.

Beard’s Provinces: South-West Province.

IBRA Regions: Esperance Plains.

IBRA Subregions: Fitzgerald.

Local Government Areas (LGAs): Jerramungup, Ravensthorpe.

Identification

Prostrate or semi-prostrate shrub to 0.5 m high and 2 m across. Branchlets slightly to prominently flexuose, glabrous. Stipules persistent.

Phyllodes continuous with branchlets, bifariously decurrent and forming opposite wings with each one extending to the next below, 1–3.5 cm long, 4–10 mm wide, coriaceous, green to subglaucous, glabrous except axils densely and minutely resin-haired; margins occasionally undulate; free portion of phyllode with obviously rounded adaxial margin, 5–15 mm long, excentrically mucronate, with main nerve obscure or superficially absent; gland not prominent.

Inflorescences rudimentary, 1-headed racemes with axes 0.5–1.5 mm long; peduncles 2–12 mm long, glabrous, sometimes descending in fruit; heads globular, 16–23-flowered, light golden. Flowers 5-merous; sepals free; petals nerveless. Pods strongly curved to twice-coiled, terete, to 2 cm long, 2–3 mm wide, thinly crustaceous, black, glabrous.

Seeds longitudinal, oblong, c. 3 mm long; aril terminal, conical.

Other uses

Suits mediterranean, oriental, contemporary, dry style, coastal & bush designs. Informal edging, pot, groundcovers, borders

Cultivation

Clay, rocky loam, sandy soils.

Soil moisture: dry for extended periods to constantly moist Sunlight: hot overhead sun to warm low sun

Links

http://www.lifestyle.com.au/plant-guide/clay-wattle-3370.aspx

http://www.worldwidewattle.com/speciesgallery/bifaria.php