Acacia crassicarpa Cunn. ex Benth., London J. Bot. 1: 379 (1842)
Thick-podded Salwood (See M.W.McDonald & B.R. Maslin, Austral. Syst. Bot . 13: 45 (2000) for other common name.)
Trees 6–25 (–30) m tall, sometimes shrubs less than 1 m tall on coastal dunes. Bark deeply rimose. Branchlets sometimes pendulous, glabrous. Phyllodes normally lanceolate-falcate, narrowly tapered at base above the pulvinus, 8–27 cm long, (0.7–) 1–4.5 cm wide, glabrous, pale green to grey-green; longitudinal nerves numerous and closely parallel (not anastomosing), 4–6 per mm; pulvinus (5–) 8–16 mm long, phyllode lamina blending gradually into the pulvinus. Inflorescences simple, 2–6 per axil; peduncles 3–10 mm long, glabrous; spikes (2–) 3–7 cm long, +/- interrupted, light golden to pale yellow. Flowers 5-merous; calyx gamosepalous; ovary densely hairy on upper half. Pods oblong to narrowly oblong, flat, (3–) 4–12 cm long, (1–) 2–4.5 cm wide, dehiscing along ventral suture, woody, the nerves transverse to transversely oblique, crowded and numerous. Seeds transverse, obloid to ovoid, 5–6 mm long, 3–4 mm wide, +/- terete, glossy, black; funicle/aril many-folded, 5–20 mm long (unextended), cream to white, ageing cream or pale yellow.
Acacia crassicarpa occurs in northern Qld, including islands in Torres Strait, and New Guinea. In Queensland it extends from Badu, Banks, Horn and Prince of Wales Islands in Torres Strait and Cape York Peninsula S to Townsville; southern outliers occur at the Burdekin River (south west of Ayr), Whitsunday Island and from Slade Point near Mackay. It is most common on sandy, lowland, coastal or near-coastal sites where it is found on sandy levees near seasonally-dry creeks and on coastal foredune systems. In New Guinea it occurs in the southern lowlands from south-eastern Irian Jaya, Indonesia, and E to the Oriomo River region of Papua New Guinea. See M.W.McDonald and B.R.Maslin, Austral. Syst. Bot. 13(1): 41–43 (2000) for further details.
Throughout its range A. crassicarpa is variable in habit and the size of its phyllodes and pods. For example, on Lizard Island, Qld, the type locality, growth habit appears strongly affected by wind shear: small trees with relatively short trunks and spreading canopies are characteristic. Relatively small pods (4–8 cm long; 1.3–2 cm wide) are also typical. A specimen collected from Palfry Island, Qld, has atypically narrow phyllodes (7–8 mm wide). See M.W.McDonald & B.R.Maslin ( loc. cit .) for further details.
Acacia crassicarpa is a member of the ‘ A. aulacocarpa group’ and based on its ventral mode of pod dehiscence is most closely related to A. lamprocarpa , A. midgleyi , A. peregrina and, more distantly, to the Indonesian endemic, A. wetarensis . However, A. crassicarpa is recognized by its large, lanceolate-falcate phyllodes which are much-narrowed at the base above the long pulvinus, light golden to pale yellow spikes which are often numerous within phyllode axils, broad, woody pods, and seeds with a cream to white, many-folded, long funicle/aril. A revision of the ‘ A. aulacocarpa group’ is presented in M.W.McDonald & B.R.Maslin, op. cit. 21–78.
Putative natural hybrids occur between A. crassicarpa and A. aulacocarpa (at Bluewater Creek near Townsville, Qld), A. crassicarpa and A. midgleyi (at Punsand Bay area near the northern tip of Cape York Peninsula, Qld) and A. crassicarpa and A. peregrina (in Western Province, PNG).
In the absence of pods A. crassicarpa may resemble specimens of A. meiosperma which have falcate phyllodes.
In recent years populations of A. crassicarpa from Papua New Guinea have shown commercial potential for use in plantations in South East Asia, particularly Indonesia and Thailand, see M.W.McDonald and B.R.Maslin (loc. cit.) for discussion.
Type of accepted name
Lizard Island, Qld, Aug. 1820, A.Cunningham 119; lecto: K, fide L.Pedley Austrobaileya 1: 147 (1978); iso: BM, NSW (fragment); para-lectotype: North Coast, Bauer (K - photograph seen, NSW - fragment).
Racosperma crassicarpum (Cunn. ex Benth.) Pedley, Austrobaileya 2(4): 347 (1987). Type: as for accepted name
[ A. aulacocarpa var. macrocarpa auct. non Benth.: C.T.White, Proc. Roy. Soc. Qld 57: 22 (1946)]
G.Bentham, Lond. J. Bot. 30: tab. 68 (1875); J.H.Maiden, Proc. Roy. Soc. Qld . 30: pl. 7, fig. 3 (1918); L.Pedley, Austrobaileya 1: 233, fig. 9J and 234, fig. 10M (1978); L.A.J.Thomson, Acacia aulacocarpa , A. cincinnata , A. crassicarpa and A. wetarensis an Annotated Bibliography (CSIRO: Melbourne.), p. 26, fig. 6 (1994), and B.R.Maslin & M.W.McDonald, A Key to useful Australian Acacias for the Seasonally Dry Tropics (CSIRO: Melbourne.), p. 33 (1996); M.W.McDonald & B.R.Maslin, Austral. Syst. Bot. 13(1): 41, figs. 8 & 42, fig. 9 (2000).
Qld: Iron Range, L.J.Brass 19271 (BRI, CANB, NSW); Horn Island, J.R.Clarkson 3934 (BRI, K, MEL, PERTH, QRS); Badu Island, J.R.Clarkson 4000 (BRI, MEL, PERTH); 64 km by road SSE of Ingham towards Townsville, R.Coveny 6936 P.Hind (A, AD, BRI, CANB, CBG, K, L, PERTH, TL, UC, US, Z); Slade Point Nature Resource Reserve, M.W.McDonald & B.R.Maslin BRM 7623 (BRI, CANB, DNA, K, NSW, PERTH); Jardine River, Bamaga, J.Moriarty 1445 (PERTH); between Starke homestead and Cape Flattery, L.J.Webb 13546 & J.G.Tracey (BRI).
The above description replaces the one given in Fl. Australia and was abstracted from the treatment provided by M.W.McDonald & B.R.Maslin (2000), Austral. Syst. Bot. 13: 39–45.