Botanical art
Prior names
Acacia bombycina
Acacia brachybotrya var. argyrophylla
Acacia brachybotrya f. argyrophylla
Common names
Silver Mulga
Silver 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. Argyrophylla from the Greek 'argyros' meaning silver and 'phylla' suffix for leaf, referring to the silvery foliage.
Distribution and status
Endemic to South Australia and found in the Flinders Ranges, Mount Lofty Ranges and the bottom of Yorke Peninsula. Grows on low hills and slopes in woodland and mallee, often in alkaline soils. An isolated occurrence from near Cromby, Victoria, is now presumed extinct. Native. Locally common in South Australia.
Herbarium regions: Flinders Ranges, Eastern, Northern Lofty, Yorke Peninsula, Southern Lofty, Green Adelaide
AVH map: SA distribution map (external link)
Plant description
Tall, erect, compact, spreading shrubs to 3 m high often the same or more across, with a golden and silvery appearance. Phyllodes oblanceolate- obovate to 5 cm long and 20 mm wide, flat and covered with short glossy silky, more or less appressed hairs. Young leaves are golden and covered in hairs. Inflorescences axillary, solitary, short racemes with globular, golden yellow flower-heads. Flowering between July and November. Fruits are dark brown linear pod to 10 cm long and 15 mm broad, raised and often rough and warty over the seeds. Margins yellowish, vein-like, somewhat constricted between the seeds. Seeds are hard, black, elliptical to ovoid to 7 mm long and 4.5 mm wide. Seed embryo type is investing.
Seed collection and propagation
Collect seeds between October 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. 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).
Location | No. of seeds (weight grams) | Number of plants | Date collected | Collection number Collection location | Date stored | % Viability | Storage temperature |
---|---|---|---|---|---|---|---|
BGA MSB | 3,335 (236.7 g) 3,335 (236.7 g) | 19 | 17-Dec-2003 | PJA67 Southern Lofty | 1-Sep-2004 | 100% | +5°C, -18°C |