Plants of
South Australia
Acacia rhetinocarpa
Leguminosae
Neat Wattle
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Regional Species Conservation Assessments per IBRA subregion.
Least concern
Near threatened
Rare
Vulnerable
Endangered
Critically endangered
Extinct
Data deficient
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Botanical art

Kath Alcock paintings: 6.

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. Rhetinocarpa from the Greek 'rhetine' meaning resin or gum and 'karpos' meaning fruit, referring to the resinous nature of the legume.

Distribution and status

Endemic to South Australia and found scattered in a few small areas near the east coast of Eyre Peninsula, east coast of Yorke Peninsula, southern Mount Lofty Ranges and in the Murray region, restricted to the Monarto area; growing in open scrub vegetation associated with Eucalyptus gracilis, E. socialis and E. incrassata on calcareous sand and loamy soil. Native. Very rare in South Australia.
Herbarium regions: Eyre Peninsula, Murray, Yorke Peninsula, Southern Lofty, South Eastern
NRM regions: Adelaide and Mount Lofty Ranges, Eyre Peninsula, Northern and Yorke, South Australian Murray-Darling Basin, South East
AVH map: SA distribution map (external link)

Plant description

Erect, compact, rounded, resinous, spreading shrubs to 1.5 m high with hairy branchlets, light yellowish-brown but becoming dark grey towards the base. Leaves obliquely obovate to 5 mm long and 3 mm wide; flat, thick, erect, yellowish-green, resinous. Inflorescences simple and axillary, with solitary globular, bright yellow flower-heads. Flowering between August and October. Fruits are long straight or curved brown pod to 3.5 cm long and 2.5 mm wide. Seeds are dark brown to black, hard oblong to elliptical seed to 4 mm long and 2 mm wide. 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. From four collections, the seed viability was average to high, ranging from 65% to 100%. This species has physical dormancy that needs to be overcome for the seed to germinate (e.g. nicking or softening the seed coat).

Seeds stored:
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LocationNo. of seeds
(weight grams)
Number
of plants
Date
collected
Collection number
Collection location
Date
stored
% ViabilityStorage
temperature
BGA5,170 (51.73 g)626-Dec-2005TJ2
Yorke Peninsula
1-Aug-200675%-18°C
BGA600 (3.98 g)2016-Dec-2005PJA114
Southern Lofty
1-Aug-200665%-18°C
BGA3,250 (30.9 g)626-Dec-2005TJ1
Yorke Peninsula
1-Aug-2006100%-18°C
BGA 
MSB
2,950 (27.64 g)
2,950 (27.64 g)
21-Dec-2005PJA118
Murray
1-Aug-200680%-18°C
BGA560 (3.73 g)1016-Jan-2017Gilbert Siding Rd
Southern Lofty
1-Nov-201790%-18°C
BGA280 (3.56 g)230-Nov-2017TST1390
Murray
30-Jun-201848%-18°C
BGA5,800 (42.6 g)1530-Nov-2017TST1389
Southern Lofty
30-Jun-201886%-18°C
BGA5,700 (49.16 g)4019-Dec-2017JRG638
Eyre Peninsula
24-Jun-202070%-18°C
Location: BGA — the seeds are stored at the Adelaide Botanic Gardens, MSB — the seeds are stored at the Millennium Seed Bank, Kew, England.
Number of plants: This is the number of plants from which the seeds were collected.
Collection location: The Herbarium of South Australia's region name.
% Viability: Percentage of filled healthy seeds determined by a cut test or x-ray.
Germination table:
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