Acacia hilliana Maiden, in A.J.Ewart & O.B.Davies, Fl. N. Territory 340; 387, pl. 27A–D (1917)
Semiprostrate, flat-topped or domed, resinous shrub mostly to 1.5 m high, 1.2–4.5 m wide. Bark splitting into flaky strips, grey to dark brownish grey. Branchlets angular to flattened towards apices, red-brown, tuberculate; ridges inconspicuous. Phyllodes solitary or in clusters of 2 or 3, linear, straight or upcurved, terete to compressed, mostly 1.7–7.1 cm long, 0.6–1.4 mm wide, coriaceous, glaucous when mature, glabrous, usually tuberculate, obscurely multistriate; gland usually 1, basal, inconspicuous, 2.8–13 mm above pulvinus. Spikes 1–4.5 cm long, golden. Flowers 5-merous; calyx 0.5–1 mm long, dissected for 2/3–3/4, glabrous; corolla 1.1–2 mm long, dissected for 1/4–1/3, glabrous; ovary non-capitate or rarely capitate, glabrous. Pods erect, very narrowly oblanceolate, narrowed basally, flat, 2–7.7 cm long, 2.5–5 mm wide, woody, with oblique nerves, opening elastically from apex; margins and seed-partitions thick. Seeds oblique to almost longitudinal, laterally compressed, 2.8–5.5 mm long, chestnut to brown; areole light brown to brown, with pale halo; funicle-aril narrowly turbinate.
Widespread and quite common in tropical W.A. and N.T., between 17S and 25S in W.A. and between 14S and 25S in the N.T. Possibly extends to Qld - see below. Grows in skeletal, red loamy sand or sand on laterite or quartzite, on slopes or ridges, near creeks, inland sand dunes or rocky plains, in open woodland, shrubland or grassland with eucalypts, acacias and spinifex. Flowers recorded from each month.
The closely allied A. citriodora , which has flat phyllodes, appears to be more common in the Mount Isa-Camooweal, Qld, while A. hilliana possibly crosses over the border into the Camooweal area (e.g. Mount Isa-Camooweal, 16 July 1973, I.B.Armitage s.n., NSW255927), but requires further investigation.
A specimen from c. 11 miles [17.7 km] W of Doomadgee on Corinda road, Qld ( S.W.L.Jacobs 1463, NSW), which has fine phyllodes (to 2.8 cm long, 0.5-0.7 mm wide) and calyces to 0.5 mm long with +/- free sepals, requires further investigation as to its relationship to A. hilliana .
Acacia hilliana is fairly consistent over a very wide range. Two variants are noted: (1) the absence of tubercles on the phyllodes and branchlets in a few specimens (e.g. Wittenoom, W.A., F.Lullfitz L6181 , NSW), and (2) the presence of a cap on the ovary in several specimens (e.g. La Grange, W.A., F.Lullfitz L6217 , NSW; 49.6 km S of Elliot, N.T., N.Forde 256 , CANB, NSW; Barrys Caves, N.T., B.Maloney , NSW126766, U).
A reputed hybrid between A. hilliana and A. stellaticeps has been collected near the Eighty Mile Beach camping ground by L.Thomson ( LXT1172A & B , PERTH).
B.R.Maslin, in J.Jessop (ed.), Fl. Centr. Australia 137 (1981) suggested that A. abbreviata may be of hybrid involving A. hilliana and A. minutifolia .
Type of accepted name
140 miles [224 km] N of C (arrow) [Survey Camp] 4, N.T., 2 July 1911, G.F.Hill 417 ; syn: BM n.v. , MEL, NSW, K; 12 miles [19 km] NW of C (arrow) 3, 12 June 1911, G.F.Hill 327 ; syn: MEL.
Synonymy
Racosperma hillianum (Maiden) Pedley, Austrobaileya 2: 349 (1987). Type: as for accepted name.
Illustration
J.H.Maiden, loc. cit .; J.R.Wheeler, in J.R.Wheeler (ed.) et al ., Fl. Kimberley Region 318, fig. 92C (1992).
Representative collections
W.A.: Sir Frederick Ra., J.R.Maconochie 1380 (NSW, NT); N of Great Sandy Desert, turnoff to La Grange Mission, I.V.Newman 657 (NSW). N.T.: Churchills Head, 80 km N of Tennant Creek, B.G.Briggs 3691 (NSW, NT, PERTH, U); 4 miles [6.4 km] NE of Kurundi Stn, M.Lazarides 5872 (CANB, NSW); Highland Rocks area, J.R.Maconochie 1089 (NSW, NT).
(NSW)
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.
