Plants of
South Australia
Acacia spilleriana
Round-leaf Mulga
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Regional Species Conservation Assessments per IBRA subregion.
Least concern
Near threatened
Critically endangered
Data deficient
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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. Spilleriana named after E. Spiller, an early Government Printer in South Australia.

Distribution and status

Endemic to South Australia and is restricted to northern Mount Lofty Ranges between Tarlee and Burra, growing in open mallee communities on low hills on calcareous soils. Native. Locally common but rare in South Australia.
Herbarium regions: Northern Lofty, Murray
NRM regions: Northern and Yorke, South Australian Murray-Darling Basin
AVH map: SA distribution map (external link)

Plant description

Bushy, compact, rounded, spreading, grey-green shrub to 3 m tall with smooth bark and densely hoary, pubescent branchlets. Leaves elliptic to oblong-elliptic less often to obovate; slightly asymmetric with a rounded apex to 3 cm long and 1.8 cm wide, firm, grey-green. New shoots sometimes silvery, marginal and main vein prominent, lateral veins obscure. Inflorescence of few globular heads from a short common peduncle with bright yellow flower-heads. Flowering between August and September. Fruits are firm, glabrous, dark grey pod to 5.5c m long and 1.8 cm wide, often with only 1-2 seeds, margin not constricted between the seed. Seeds are hard, black, ellipsoid to ovoid seed to 6 mm long and 4 mm wide. Seed embryo type is investing.

Seed collection and propagation

Collect seeds between September and December. 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 two collections, the seed viability was high, ranging from 95% 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:
LocationNo. of seeds
(weight grams)
of plants
Collection number
Collection location
% ViabilityStorage
BGA1,200 (30.56 g)3028-Nov-2005Hallelujah Hills
Flinders Ranges
8,310 (249.3 g)
9,400 (282.87 g)
Northern Lofty
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.