Plants of
South Australia
South Australia
Botanical art
Etymology
Acacia from the Greek 'akakia' and derived from 'ake' or 'akis' meaning a sharp point or thorn and 'akazo' meaning to sharpen. Dioscorides, the Greek physician and botanist used the word in the 1st century AD for the Egyptian thorn tree, Acacia arabica. Paradoxa from the Greek 'para' meaning near and 'doxa' meaning glory, splendour; may refer to this unattractive and thorny shrub being a showy plant when in full bloom.
Distribution and status
Found in the southern part of South Australia, growing on hard alkaline red duplex, hard acidic or neutral yellow duplex and shallow calcareous loamy soil in woodland, open forest and open scrub vegetation. Also found in Queensland, New South Wales and Victoria and naturalised in Western Australia and Tasmania. Native. Common in South Australia. Uncommon in Queensland. Common in New South Wales and Victoria.
Herbarium regions: Flinders Ranges, Eastern, Eyre Peninsula, Northern Lofty, Murray, Yorke Peninsula, Southern Lofty, Kangaroo Island, South Eastern, Green Adelaide
NRM regions: Adelaide and Mount Lofty Ranges, Eyre Peninsula, Kangaroo Island, Northern and Yorke, South Australian Arid Lands, South Australian Murray-Darling Basin, South East
AVH map: SA distribution map (external link)
Plant description
Straggly to dense shrub or tree to 4 m high with ribbed branchlets, often arched down. Leaves erect, asymmetric, usually lanceolate, sometimes narrowly oblong-elliptic to 30 mm long and 7 mm wide; glabrous to sparsely hairy; abaxial margin usually undulate, acute or obtuse, with a pungent mucro; midrib usually off-centre; stipules spiny. Flower-spike axillary, single with globular, golden flower-heads. Flowering between August and October. Fruits are dark brown linear to narrowly oblong pod to 60 mm long and 5 mm wide, densely hairy. Seeds are hard, dark brown to black, oblong to 6 mm long and 3 mm wide. Seed embryo type is investing.
Seed collection and propagation
Collect seeds between October and January. Collect mature pods that are turning brown with hard, dark seeds inside. Place the pods in a tray and leave to dry for 1-2 weeks or until the pods begin to split. Then rub the dried pods to dislodge the seeds. Use a sieve to separate any unwanted material. Store the seeds with a desiccant such as dried silica beads or dry rice, in an air tight container in a cool and dry place. Seed viability is usually high. This species has physical dormancy that needs to be overcome for the seed to germinate (e.g. nicking or softening the seed coat).
