Acacia sinuata (Lour.) Merr., Trans. Amer. Philos. Soc. 24 (1935)
Woody climber. Branchlets with patchy or sparsely distributed long weak crisped hairs, with wide ribs and scattered recurved prickles up to 2 mm long along the ribs. Leaves: petiole 1.5–3.5 cm long, with a prominent elliptic gland at about the middle; rachis 5–10 cm long, with scattered abaxial prickles on some leaves, gland present at base of uppermost pair of pinnae; pinnae 5–6 pairs, 5–7 cm long; leaflets 12–24 pairs per pinna, 6.5–9 mm long, 1.8–2.5 mm wide, oblong, obtuse, mucronulate, asymmetrically truncate at base, midrib oblique (arising at leading edge of leaflet and extending to about the middle of the leaflet at the apex), 3 or 4 lateral veins with distinct reticulum between them, with sparse long loose hairs on both surfaces or hairs confined to margins. Inflorescences single or in 2’s or 3’s in upper axils, the subtending leaves often not developing and heads forming a raceme or panicle; head globular, 30–40-flowered; peduncles 1.5–2 cm long, indumentum similar to that of branchlets; buds red or purplish red, open flowers cream. Flowers 5merous, sessile; calyx 1.5–3 mm long, shortly lobed, glabrous; corolla 2.5–3 mm long, lobed to about level of the calyx. Pods and seeds not seen.
Known from only two localities in north-east Qld. The Mossman plants were eradicated in 1974 because of their weed potential; a new population, at Gregory Falls, was discovered in 1998.
A. sinuata from New Guinea has more leaflets and pinnae than the Qld specimens but the venation and indumentum are the same. Collectors have referred to it as a small short-boled or multistemmed tree, or sprawling shrub.
There is a second species represented at herb. BRI under A. sinuata , but which is not included in the above description. It is described by collectors as a bush or climber; it differs from A. sinuata , as described here, in having more pinnae and more leaflets per pinna. Furthermore, its leaflets have a less distinct venation, they are shortly appressed pubescent beneath and have a short but distinct petiolule (0.4 mm long). Specimens referable to this species have been collected in the Townsville-Ayr region and on from the Mulgrave valley (a little south of Cairns), all in open forest, not rainforest as for A. sinuata . They match a collection from Guangdong Prov., China, received at BRI as A sinuata .
Qld: Rocky Point area, ca 11 km N of Mossman, 19 Sept. 1974, A.J.Twomey s.n. (BRI); Gregory Falls, Reserve 842 Parish of Johnstone, 17 35’S 145 52’, B.P.M.Hyland 13817 (BRI, ex QRS – distributed as A. albizioides ).
This species was not included in the Fl. Australia treatment of Acacia . The above treatment, which is based on Qld specimens, was provided by L.Pedley.