Kath Alcock paintings: 3
Racosperma retinodes var. uncifolia
Acacia retinodes var. uncifolia
Acacia rhetinodes, orth.var., partly
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. Uncifolia from Latin meaning hooked leaf, referring to the characteristically hooked mucro found on the phyllodes.
Distribution and status
The species has a disjunct distribution in coastal and near coastal areas of South Australia, on Kangaroo Island and the southern Fleurieu Peninsula, growing in coastal habitats, on dunes and sandy soils over limestone. Also found in Victoria and Tasmania. Native. Common in South Australia. Common in Victoria. Rare in Tasmania.
Herbarium regions: Southern Lofty, Kangaroo Island
NRM regions: Adelaide and Mount Lofty Ranges, Kangaroo Island
AVH map: SA distribution map (external link)
Large rounded shrub or small tree to 10 m high with single or several main stems from near ground level and smooth, grey to dark brown bark. Branchlets reddish, angular at first but soon terete, glabrous, marked with rather prominent raised leaf bases where phyllodes have fallen. Phyllodes to 80 mm long and 15 mm wide, oblanceolate to narrowly oblanceolate, rather abruptly narrowed at apex into a delicate recurved-uncinate point, straight or shallowly recurved, glabrous, green to grey-green, midrib slightly eccentric, not pronounced. Inflorescences axillary spike with 5–12 globular yellow flower-heads. Flowering between October and December. Fruits are brown, linear pods to 160 mm long and 8 mm wide, often slightly constricted between the seeds, straight to slightly curved, glabrous. Seeds are hard, dark brown to black, ovoid to 4 mm long and 2.5 mm wide, surrounded by a yellowish aril. Seed embryo type is investing.
Seed collection and propagation
Collect seeds between November 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).