Prior names
Acacia brachybotrya var. spilleriana
Common names
Round-leaf Mulga
Spiller's Wattle
Round-leaf Mulga-bush
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. 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
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).
| Location | No. of seeds (weight grams) | Number of plants | Date collected | Collection number Collection location | Date stored | % Viability | Storage temperature |
|---|---|---|---|---|---|---|---|
| BGA | 1,200 (30.56 g) | 30 | 28-Nov-2005 | Hallelujah Hills Flinders Ranges | 9-Aug-2006 | 100% | -18°C |
| BGA MSB | 8,310 (249.3 g) 9,400 (282.87 g) | 70 | 1-Dec-2006 | KHB65 Northern Lofty | 1-Aug-2007 | 95% | -18°C |
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.