8 MIMOSACEAE 
pulvinus. Inflorescences on simple axillary 
peduncles, 1-4 per axil. Spikes yellow, 55-75 mm 
long, 4-6 mm wide, with flowers interrupted; 
peduncle 4-7 mm long, glabrous, rachis glabrous. 
Pods stipitate, brown, linear to oblong, coiled, flat 
but strongly undulate, 65-130 mm long, 10-18 mm 
wide, woody, glaucous, glabrous, obliquely 
reticulately nerved, acute. Seeds oblique in pod, 
brown, discoid, 4-5 mm long. Flowering: Feb - July; 
fruiting: July - Oct. Fig. 2 Black Wattle 
From northern NT to Cape York and New Guinea 
and common in the DR. Found in and along margins 
of monsoon forests, margins of swamps and coastal 
dunes; also widely planted. 
*A. catechu (L.f.) Willd. var. sundra (Roxb.) Kurz 
Erect shrub or tree, 4-5 m high. Bark light brown, 
fissured. Branchlets terete or slightly angular with 
paired, slightly recurved thorns at nodes, glabrous. 
Stipules persistent, narrow-triangular, 1 mm long, 
glabrous. Leaves bipinnate. Pulvinus 4-5 mm long, 
glabrous. Leaf rachis 49-150 mm long, 15-21 pairs 
of pinnae per leaf, hairy on upper surface, jugary 
glands present on last 2 pairs of pinnae, interjugary 
glands absent; pinnae 20-42 mm long, 31-43 pairs of 
leaflets per pinna; leaflets linear-oblong, flat, 3-5 mm 
long, 0.9-1 mm wide, L/W 4-5, lower surface slightly 
paler than the upper surface, glabrous. /nflorescences 
on simple axillary peduncles. Spikes pale yellow, 
50-130 mm long, 10 mm wide, flowers interrupted; 
peduncle 10-18 mm long, glabrous, rachis glabrous. 
Pods stipitate, brown, linear to oblong, straight, raised 
over seeds alternately on each side, 30-70 mm long, 
12-18 mm wide, chartaceous, glabrous, transversely 
reticulately nerved, apiculate. Seeds transverse in pod. 
Flowering: Feb; fruiting: immature pods collected in 
April. Fig. 2 
Native to Sri Lanka, Burma and India. In the DR 
restricted to an introduction in the Darwin Botanic 
Gardens and Bullocky Point. 
A. conspersa F.Muell. 
Erect shrub or spindly tree, 2-7.5 m high, slightly 
mealy or hoary. Branchlets faintly ribbed, densely 
tomentose, hairs hyaline. Stipules persistent, reddish, 
triangular, 1-2 mm long, pubescent, fimbriate with 
age. Pulvinus 1-3 mm long, hairy. Phyllodes straight 
or slightly curved, narrowly elliptic, 32-80(130) mm 
long, 4-8 mm wide, L/W 6-15, sparsely to densely 
pubescent, hairs hyaline, longitudinal veins 
numerous and closely spaced, one more prominent, 
anastomoses absent, base attenuate, apex acute, mucro 
oblique or hooked. Glands 1-2, near base and on 
Acacia 
dorsal margin. Inflorescences on simple axillary 
peduncles, 1-2 per axil. Spikes yellow, 20-50 mm 
long, 3-5 mm wide, densely flowered; peduncle 
1-1.5 mm long, hairy, rachis hairy. Pods stipitate, 
olivaceous to brown, linear to oblong, slightly curved, 
cylindrical, 42-90 mm long, 3-4 mm wide, coriaceous, 
vernicose, glabrous or hairy, longitudinally wrinkled, 
acute. Seeds longitudinal in pod, brown, faintly 
mottled, flattened oblong, 4-5 mm long, 2-3 mm wide. 
Flowering: Apr - Oct; fruiting: Sept - Oct. Fig. 2 
An NT endemic found from the DR to the Gulf 
with one odd record for central Australia. Rare in the 
DR where known from one locality south of Adelaide 
River. 
A. difficilis Maiden 
Erect shrub or tree, 2.5-9 m high. Bark reddish, 
fibrous and fissured when old. Branchfets terete, 
glabrous to densely tomentose, hairs hyaline. 
Stipules caducous. Pulvinus 6-9 mm long, glabrous 
or hairy. Phyllodes curved, dimidiate, broadest a 
middle or falcate-dimidiate, 55-200 mm long, 15- 
35(51) mm wide, L/W 2.6-7.6, glabrous or densely 
tomentose, hairs hyaline, longitudinal veins 
numerous and closely spaced, 3(4) more prominent, 
anastomoses sparse or absent, base attenuate and 
oblique, apex acute or obtuse and asymmetric, mucro 
oblique. Glands 1, at pulvinus. Inflorescences on 
simple axillary peduncles, 1-5 per axil or extended 
axillary racemes, 2-6 heads per raceme, axis length 
20-75 mm long. Spikes yellow, 25-39 mm long, 
4-6 mm wide, densely flowered; peduncle 2-7 mm 
long, glabrous or hairy, rachis glabrous. Pods 
stipitate, brown, linear to oblong, straight or curved, 
cylindrical, 30-155 mm long, 3-4 mm wide, 
coriaceous, subglaucous or pruinose, glabrous 
or hairy, longitudinally wrinkled, acute. Seeds 
longitudinal in pod, black, slightly flattened oblong, 
5-9 mm long, 2.7-3.7 mm wide. Flowering: June - 
Sept; fruiting: Aug - Oct. Fig. 2 
In the Top End north of 18° S and extending into 
the Qld Gulf. Common in the DR on alluvial sandy 
soils associated with levees and open forest. 
A. dimidiata Benth. 
Erect shrub or small tree, 2-4 m high. Branchlets 
ribbed, densely tomentose, hairs erect, silvery. 
Stipules persistent, brown, narrow-triangular, 2 mm 
long, pubescent. Pulvinus 3-9 mm long, hairy. 
Phyllodes straight, dimidiate, broadest below 
middle, (37)70-155 mm long, (16)35-95 mm wide, 
L/W 1.2-2.4, slightly vernicose, sparsely tomentose, 
hairs closely appressed, hyaline, primary veins 4-5, 
