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Photographer: E. Thoma
Photographer: B.R. Maslin
Photographer: B.R. Maslin
Photographer: B.R. Maslin
Photographer: B.R. Maslin
Photographer: B.R. Maslin
Photographer: J. Maslin
, LSWE 7021, lab photo by FM.jpg)
Seed from one herbarium voucher. Scale in mm. Photographer: F. McCallum.
Botanical name
Acacia citrinoviridis Tindale & Maslin, Nuytsia 2: 86, figs 1, 3C-D & 4 (1976)
Common name
River Jam (preferred common name), Black Mulga and Pilbara Jam (Pilbara district), Milhan Tree (Ashburton district) and Wantan (Murchison-Gascoyne region)
Aboriginal name
Jarrawayi (Ngarluma and Yindjibarndi) Yilyurru (Kariyarra), Jarparri, Jarwayi, Jarbarri or Jarrwayi (Kurrama), Jarrbari (Banyjima) and Kuyuwarra (Putijarra)
Description
Attractive, shapely tall shrubs or trees 3.5-12 m high but on open, well-watered sites it may reach 15-18 m tall and spread to 5-15 m across, normally with a single, straight trunk (to about 30 cm diameter at breast height) or sometimes with up to about 3 main stems from ground level, young plants have a dense, bushy habit; crown dense, often rounded, occasionally semi-pendulous and of a beautiful silvery green, greyish green or blue-grey colour. Bark dark grey, longitudinally fissured on trunks and main branches. Branchlets with short, silvery white appressed hairs towards ends but soon becoming glabrous with age further down the stem. New shoots densely clothed with silky, iridescent, citron yellow hairs which turn silvery white with age. Phyllodes falcate (i.e. shallowly to prominently recurved, broadest near the middle and narrowed at both ends), narrowly elliptic, (5-) 6-12 (-17) cm long, mostly (6-) 7-13 (-20) mm wide but a few phyllodes on some specimens may reach 4-5 mm wide, thinly coriaceous, not rigid, wide-spreading but commonly with a tendency to droop on ultimate branchlets, the young and adolescent phyllodes sericeous (due to dense layer of short, straight, appressed hairs) and silvery, silvery grey or blue grey, becoming glabrous, green (due to loss of hair layer) and slightly shiny with age; parallel longitudinal nerves numerous, fine and close together, the central nerve (and a nerve either side of it) a little more pronounced than the rest, nerves usually obscured by the dense indumentum on young and adolescent growth, with a discrete, narrow, yellowish, non-resinous marginal nerve; apex acute to acuminate and not spiny. Inflorescences simple; peduncles 1-7 mm long, densely appressed silvery hairy (hairs rarely patent or pale yellow); receptacle very densely clothed with pale yellow to golden (occasionally silvery white), soft, spreading hairs, indumentum sometimes sparser (rarely absent) in fruit; spikes prolific, 8-32 mm long, the bright yellow flowers densely arranged. Flowers 5-merous; sepals ±free. Pods narrowly oblong, flat but a little rounded over seeds and not constricted between them, 2-12 cm long, 10-15 mm wide, thinly coriaceous-crustaceous, straight, not resinous, velvety or silky by dense, yellow or (especially when mature) silvery white hairs, light brown to greyish brown, abruptly constricted at base into a short stipe. Seeds longitudinal in the pods, broadly obloid-ellipsoid to almost globose, flattened, 5-6 mm long, dark brown to blackish (sometimes pale-coloured at centre); aril cream-coloured.
Characteristic features
Attractive graceful trees beautiful with silvery green, greyish green or blue-grey crown; confined to water courses. New shoots densely clothed with silky, iridescent, normally citron yellow hairs (which age silvery white). Phyllodes falcate, acute to acuminate, densely silvery sericeous aging glabrous, finely multi-nerved. Spikes densely flowered; peduncles short (1-7 mm), hairy. Pods broad (10-15 mm wide), flat, velvety or silky by dense, yellow or (especially when mature) silvery white hairs, shortly stipitate. Seeds flattened.
Distribution and ecology
Occurs in northwest W.A. from near the Gascoyne River north to the Fortescue River in the Pilbara. Normally found on the banks and floodplains of major river systems and some minor creeks. On rare occasions it grows away from watercourse at the foot of or on top of mesas in the Robe Valley and elsewhere in the west Pilbara, but always in water gaining situations. Grows in a variety of fine texture soils over coarse gravel and pebbles which are typically slightly to strongly alkaline (pH 7.5-9).
Flowering and fruiting period
Flowering appears to be somewhat erratic and has been recorded on plants from February to August but the main flowering flush is in April and May. Pods with mature seed has been collected between late September and late October. As with many other arid zone acacias, it appears that flowering (and possibly also fruiting) in River Jam is dependent upon the timing and intensity of rainfall events.
Affinities
Related to A. subcontorta and A. distans (see these species for discussion). River Jam is superficially similar to A. hamersleyensis which is distinguished by its straighter, more coriaceous, less hairy phyllodes, broader pods with spreading hairs, and receptacles which are not densely golden hairy. Rare putative hybrids between A. ancistrocarpa and A. citrinoviridis occur between Munjina and Roy Hill Station in the valley of the Fortescue River (see A. ancistrocarpa x citrinoviridis), and possibly between A. citrinoviridis and A. tumida var. pilbarensis near Cane River Station, about 80 km southeast of Onslow (see A.? citrinoviridis x tumida var. pilbarensis).
Notes
This species has a moderately fast growth rate, long life span (over 40 years), good coppicing ability and a propensity to root sucker (Doran and Turnbull 1997).
It does not appear to have any forage value and has no indicator value for rangeland condition (Mitchell and Wilcox 1994).
According to Doran and Turnbull (1997) this species has potential for fuelwood, small posts, shade, shelter, erosion control and ornamental purposes; the wood is dense (810 kg/m3) with a dark brown, moderately durable heartwood.
Acacia citrinoviridis has horticultural potential for arid and semi-arid areas, particularly on account of its long life span, shapely growth form, profusion of flowers, its attractive, silvery green, grey-green or blue-grey foliage and golden new shoots and young pods. It is likely, however, to require supplementary watering for successful establishment. Also, plants can become untidy when old.
Fox and Dunlop (1983) provide notes on seed viability germination responses using hot water treatments. Some plants in the field show the seed heavily predated by seed-eating grubs.
Traditional aborigines have been reported to coarsely grind and dry the seed of this species and eat them uncooked (Scott 1972). Also, as reported by Juluwarlu Aboriginal Corporation (2003), Ngarluma and Yindjibarndi peoples used the wood of A. citrinoviridis to make mawurndu (dueling and punishment spears), wirra and birrirdi (boomerangs), juna and wanu (fighting sticks) and the branches were used to build a burrumia (bough shelter) (Young 2007). Edible gum was also obtained from lesions on the trunk and pilu (witchetty grubs) were found in the roots.
Conservation status
Not considered rare or endangered.
Origin of name
The botanical name is derived from the Latin citrinus (lemon-yellow coloured) and viridis (green), in reference to general colour impression of the young shoots and pods which are covered by a dense layer of yellow hairs.
References
Doran, J.C. and Turnbull, J.W. (1997). Australian trees and shrubs: species for land rehabilitation and farm planting in the tropics. ACIAR Monograph No. 24. pp. 384. (Australian Centre for International Agricultural Research: Canberra.)
Fox, J.E.D. and Dunlop, J.N. (1983). Acacia species of the Hamersley Ranges, Pilbara Region of Western Australia. Mulga Research Centre. Occasional Report No. 3. pp. 94. (Western Australian Institute of Technology: Bentley.)
Juluwarlu Aboriginal Corporation (2003). Wanggalili: Yindjibarndi and Ngarluma Plants. pp. 128. (Juluwarlu Aboriginal Corporation: Roebourne, Western Australia.)
Mitchell, A.A. and Wilcox, D.G. (1994). Arid shrubland plants of Western Australia. Edn. 2. pp. 478. (University of Western Australia Press in association with the Department of Agriculture: Perth.)
Scott, M.P. (1972). Some Aboriginal food plants of the Ashburton District, Western Australia. Western Australian Naturalist 12(4): 94-96.
Young, L. (2007). Lola Young: Medicine Woman and Teacher. Complied by Anna Vitenbergs. pp. 160. (Fremantle Arts Centre Press: Fremantle.)