Acacia 
Widespread across the Top End and extending 
into the Kimberley. Common in the DR in open 
forest on lateritic soil. 
A. pachyphloia W.Fitzg. & Maiden 
Tree, 3-10 m high. Bark off-white to yellowish grey, 
corky. Branchlets pendulous, angular, glabrous. 
Stipules caducous, spiny in juvenile plants. Leaves 
bipinnate. Pulvinus 2-3 mm long, glabrous. Leaf 
rachis 38-140 mm long, 2-4 pairs of pinnae per leaf, 
glabrous, jugary glands present, interjugary glands 
absent; pinnae 75-155 mm long, 13-34 pairs of leaflets 
per pinna; leaflets narrowly elliptic’ to 
oblanceolate, 5-28 mm long, 2-7 mm wide, L/W 2.5- 
5.6, concolorous, glabrous. /nflorescences on simple 
axillary peduncles or extended axillary racemes or 
panicles, 6-11 heads per raceme, axis length 40-100 
mm long. Heads globular, white to cream, 14-18 mm 
wide; peduncle 20-54 mm long, glabrous. Pods 
stipitate, brown, linear to oblong, straight, raised over 
seeds, 50-93 mm long, 12-15 mm wide, woody, glab- 
rous, longitudinally reticulately nerved, acute. Seeds 
longitudinal in pod, brown, broadly oblong, 12 mm 
long, 9-10 mm wide. Flowering: irregularly through- 
out the year; fruiting: mostly June - July. Fig. 7 
Disjunctly distributed from the Kimberley to the 
western Top End and southern Arnhem Land. 
Restricted to southern part of DR in woodland on a 
wide variety of soils. 
A. pallidifolia Tindale 
Tree, 4-6 m high. Bark off-white to grey, corky. 
Branchlets terete, sparsely to densely tomentose, hairs 
erect, hyaline. Stipules persistent, reddish, spinose, 
1 mm long, pubescent, stipular spines to 10 mm long 
present on juvenile growth. Leaves bipinnate. Pulvinus 
3-9 mm long, hairy. Leaf rachis 90-245 mm long, 
8-14 pairs of pinnae per leaf, hairy, jugary glands 
present at terminal pair of pinnae, interjugary glands 
absent; pinnae 45-95 mm long, (13)20-23 pairs of 
leaflets per pinna; Jeaflets linear-oblong to lanceo- 
late, flat or slightly recurved, 6-14 mm long, 1-4 mm 
wide, L/W 3.6-6, lower surface slightly paler than 
the upper surface, glabrous. Inflorescences on 
simple axillary peduncles, 1-2 per axil. Heads 
globular, pale yellow, 9-13 mm wide; peduncle 
16- 53 mm long, with involucel at or just below 
middle, slightly hairy. Pods stipitate, brown, linear to 
oblong, straight, flat, 55-150 mm long, 12-22 mm 
wide, slightly woody, glabrous, longitudinally 
reticulately nerved, acute. Seeds longitudinal in pod, 
pale brown, discoid, 9 mm long, 8.5 mm wide. 
Flowering: Sept - Oct; fruiting: Nov. Fig. 9 
MIMOSACEAE 17 
The taxon described here is tentatively treated as 
conspecific with the poorly known A. pallidifolia 
from the VRD. Outside the VRD known from Kakadu 
NP, near Adelaide River and near the Bark Hut Inn. 
Found in open woodland on stony hills usually with 
E. tectifica. This taxon is also similar to another 
species, long known informally as A. ‘calcigera’, 
which occurs further south in the Katherine area. 
A. pellita O.Schwarz 
Erect shrub or slender tree, 2-8 m high. Branchlets 
strongly ribbed and angular, densely tomentose, hairs 
erect, hyaline. Stipules persistent, brown, triangular, 
1.5-2 mm long, pubescent. Pulvinus 6-10 mm long, 
hairy. Phyllodes straight, broadly elliptic, 70-180 mm 
long, 25-70 mm wide, L/W 2.1-4, densely tomentose, 
hairs erect, hyaline, primary veins 3, concurrent with 
lower margin near base, secondary veins oblique or 
penniveined, reticulate, base oblique, apex acute to 
obtuse, mucro straight. Glands prominent, 2, near 
mucro and at pulvinus. Inflorescences typically on 
simple axillary peduncles or rarely on short axillary 
shoots, 3 heads per raceme, axis length 20 mm long. 
Spikes yellow, 35-50 mm long, 5-6 mm wide, loosely 
to densely flowered; peduncle 3-4 mm long, hairy, 
rachis hairy. Pods sessile, greyish, linear to oblong, 
coiled and intertwined, persisting on rachis, raised 
over seeds, 4-5 mm wide, coriaceous, hairy, nerves 
obscure, obtuse. Seeds longitudinal in pod, brown, 
broadly oblong, 4.5-5 mm long, 3-4 mm wide. 
Flowering: June - Aug; fruiting: pods persisting 
throughout the year. Fig. 9 
The Kimberley and western Top End north of 
17° S. Found in the southern part of the DR in shady 
localities on sandy alluvium along creek lines. 
A. platycarpa F.Muell. 
Shrub or slender tree, 3-8 m high, usually pruinose. 
Bark reddish, smooth. Branchlets terete, pruinose, 
glabrous. Stipules persistent, brown, broad-triangular, 
1 mm long, pubescent. Pulvinus 3-4 mm long, 
glabrous. Phyllodes straight or curved, dimidiate and 
generally broadest towards base, 52-190 mm long, 10- 
67 mm wide, L/W 2.5-5.2, slightly pruinose, glabrous, 
primary veins 3-4, concurrent with lower margin near 
base, secondary veins oblique or penniveined, 
reticulate and prominent, base oblique, apex acute or 
obtuse. Glands prominent, 4-5, at pulvinus and scat- 
tered along dorsal margin. Inflorescences terminal 
panicles, axis length 100-210 mm long. Heads globu- 
lar, white to cream, 6-9 mm wide; peduncle 7-16 mm 
long, glabrous. Pods stipitate, brown, linear to 
oblong, straight or slightly curved, flat, 75-150 mm 
long, 18-30 mm wide, woody, pruinose, glabrous, 
