Acacia retivenea F.Muell., Fragm . 3: 128 (1863)
Erect, open shrub 1–3 m high. Branchlets crispate-villous or tomentose, rarely glabrous. Stipules 2–5.5 mm long. Phyllodes inequilaterally elliptic to widely elliptic, ovate or subrotund, 3.5–12 cm long, 2.5–6 cm wide, with shallowly crenate upper margin, rounded-obtuse to retuse, usually crispate-villous or tomentose, with 3 or 4 distant, strongly raised main nerves, prominently and closely reticulate. Inflorescences mostly simple and initiated synchronously with phyllodes on new shoots to form ‘false’ terminal racemes, 1 per axil; peduncles 17–40 mm long, crispate-villous to tomentose; heads globular, 10 mm diam., densely 71–105-flowered, golden; bracteoles exserted or not. Flowers 5-merous; sepals 1/2–3/4-united. Pods straight or one margin curved, flat, 2.5–6.2 cm long, 1–2 cm wide, coriaceous or hard-crustaceous, densely hairy or subglabrous at maturity. Seeds transverse, broadly elliptic to oblong, 4.8–6 mm long, brown-black; aril apical.
The species is widespread in inland northern Australia from W.A. through N.T. to Qld.
Most closely related to A. auricoma .
The specific epithet has often been spelled ‘retivenia’, beginning with Bentham, but Mueller clearly intended the spelling adopted here, for he used this spelling in the protologue and in his subsequent publications, fide R.S.Cowan & B.R.Maslin, Nuytsia 10: 75 (1995).
Acacia retivenea comprises two, well-marked, mostly allopatric subspecies.
Stipules 2–3 x 1.5–2 mm. Phyllodes widely elliptic to subrotund, densely tomentose (felty to touch), rarely glabrous. Bracteole blade thick fleshy, exserted in buds. Pods densely tomentose
subsp. retivenea
Stipules 3–5.5 x 3–5 mm. Phyllodes elliptic to ovate, with indumentum normally less dense than above. Bracteole blade thin, flat, not conspicuously exserted in buds. Pods sparsely hairy to subglabrous at maturity (indumentum denser on young pods)
subsp. clandestina
Acacia retivenea F.Muell. subsp. retivenea
Stipules ovate, rounded basally, 2–3 mm long, 1.5–2 mm wide, densely tomentose. Phyllodes broadly elliptic to subrotund, 3.5–6.5 cm long, 28–58 mm wide, retuse and mucronulate, densely tomentose, rarely glabrous and lucid. Peduncles 17–32 mm long, tomentose; bracteoles conspicuously exserted in young buds, the lamina thick and fleshy, glabrous or sparsely puberulous. Pods often obtuse-apiculate, flat, raised over seeds, 2.5–4 cm long, 12–16 mm wide, coriaceous, one margin curved, densely tomentose.
Widespread from Fitzroy Crossing and King Leopold Ra. (c. 130 km NNW of Fitzroy Crossing) in the Kimberley area, W.A., across the N.T. to Mount Isa, Qld , with outliers near Pine Creek (c. 190 km SE of Darwin) and Reynolds Ra. (c. 150 km NNW of Alice Springs), N.T., and Torrens Creek., Qld. Grows in shallow sandy soil in rocky ground, in low open woodland and tall open shrubland, often associated with Eucalyptus brevifolia and Triodia .
This subspecies is normally characterised by its dense, conspicuous indumentum on the phyllodes, but a glabrous variant has been recorded in a few localities in Qld (e.g. c. 96 km ESE of Camooweal Township, Perry 762 , CANB n.v. , PERTH) and N.T. (e.g. between Frewena and Qld border, A.S.Cudmore s.n. , DNA28590). According to L.Pedley, Austrobaileya 1: 207 (1978), the glabrous variant in Qld occurs between Camooweal and Mount Isa and is sympatric with the normal form.
Of the several characters distinguishing this subspecies from subsp. clandestina , the most obvious are the nature of its bracteoles, the shape and indumentum of its phyllodes, and the shape and size of its stipules.
Type of accepted name
Short’s Ra., [N.T.], J.Mcdouall Stuart ; holo: MEL; iso: K.
Synonymy
Racosperma retiveneum (F.Muell.) Pedley, Austrobaileya 2: 354 (1987). Type: as for accepted name.
Illustration
M.Simmons, Acacias Australia 2: 139 (1988).
Representative collections
W.A.: between new Halls Creek and Carolyn Pool on site of Duncan Hwy, K.F.Kenneally 7228 (CANB, K, MEL, PERTH). N.T.: 19.3 km S of Renner Springs, N.Forde 27 (PERTH). QLD: Mount Isa, P.E.Conrick 1507 (PERTH); 96.5 km ESE of Camooweal Township, R.A.Perry 762 (PERTH).
Acacia retivenea subsp. clandestina R.S.Cowan & Maslin, Nuytsia 10: 76 (1995)
Stipules broadly ovate, cordate basally, 3–5.5 mm long, 3–5 mm wide, suberect-villous, marginally glabrescent. Phyllodes elliptic to ovate, 4.5–6.5 (- 12) cm long, 25–55 mm wide, rounded, mucronulate, villous to crispate-villous. Peduncles 20–40 mm long, densely crispate-villous or villous; bracteoles spathulate, the lamina thin, inconspicuously exserted being appressed to surface of young buds. Pods straight-edged, mucronulate, convex, 4.3–6.2 cm long, 15–20 mm wide, hard-crustaceous, crispate-villous, villous or cobwebby-villous, sparsely hairy to subglabrous at maturity.
Scattered across the inland Pilbara from near Quarry Hill (c. 125 km W of Tom Price) and Barlee Ra. (c. 190 km SW of Tom Price) E to Paterson Ra. and Rudall R. Natl Park on the western edge of the Great Sandy Desert and also in the southern Kimberley in Edgar Ra. (c. 110–190 km SE of Broome) and Bungle Bungle Natl Park (c. 120 km NE of Halls Creek), W.A. Usually grows on rocky creek beds and on hillsides in tall shrubland, often associated with Grevillea wickhamii and, in the Kimberley, with Acacia tumida .
Type of accepted name
Upper Rudall R. area, W.A., 5 Sept. 1971, B.R.Maslin 2127 ; holo: PERTH; iso: BRI, K, NSW, US.
Representative collections
W.A.: 16 km NE of Bungle Bungle Outcamp, 5 km S of Mining Camp ‘Playground’, K.F.Kenneally 9215 (BRI, PERTH); 29 km E of Ranger’s Residence, outside Hamersley Ra. Natl Park, I.Solomon 16 (BRI, CANB, PERTH).
(RSC & BRM)
The information presented here originally appeared on the WATTLE CD-ROM which was jointly published by the Australian Biological Resources Study, Canberra, and the Department of Parks and Wildlife, Perth; it was produced by CSIRO Publishing from where it is available for purchase. The WATTLE custodians are thanked for allowing us to post this information here.
