Viscid, somewhat aromatic shrub, 1–5 m high; branchlets sometimes flexuose, rarely pruinose, terete or angled towards extremities, usually with appressed, minute hairs on ribs and either non-resinous or with a thin layer of resin between ribs. Phyllodes elliptic or narrowly elliptic to lanceolate, rarely oblong-elliptic, oblanceolate-elliptic or linear, (3–)5–14 cm long, (3–)7–30 mm wide, straight to slightly curved, thin, resinous-punctate, with appressed, minute hairs on margins and midrib, sometimes glabrous, mostly acute or acuminate; veins 1 or 2, lateral veins few to numerous; gland 0–8 mm above pulvinus. Peduncles commonly 2 per axil, (2–)4–8(–11) mm long, sometimes in 2–6-headed racemes with rachis 2–4 mm long, subglabrous to densely puberulous, basal bract mostly caducous; heads globular, 25–40(–45)-flowered, pale yellow to lemon-yellow. Flowers 5-merous; sepals united. Pods linear to narrowly oblong, 3–9 cm long, 4–6 mm wide, thinly coriaceous to firmly chartaceous, glabrous; seeds longitudinal, obloid to obloid-ellipsoid, 4–5 mm long, shiny, dark brown to black, aril terminal.
VRiv, GipP, OtP, WaP, Gold, CVU, GGr, EGL, EGU, HSF, HNF, OtR, Strz, MonT, HFE, VAlp. Also Qld, NSW.
5 varieties, 4 in Victoria.
This species was previously characterised by the phyllodes only having 1 main vein. However, the definition of A. leprosa has expanded to include plants with 1 or 2 veins per phyllode. Of the 4 varieties of A. leprosa in Victoria only A. leprosa var. uninerva has phyllodes with a single vein, the other 3 varieties have 2 veins per phyllode. Acacia leprosa is now principally differentiated from A. verniciflua on the basis of branchlet indumentum. Acacia verniciflua has brachnlets with scarcely raised ribs that are more or less glabrous with dense resin in the space between them, while A. leprosa has strongly ribbed branchlets that are usually hairy on ribs and have little to no resin in the space between ribs (see Maslin & Murphy 2009). The inter- and infraspecific taxonomy of this group is incredibly complicated, and as with previous treatments, many of the characters used in this account may prove to be arbitrary at best.
Besides A. verniciflua and allied species (A. rostriformis, A. exudans, and A. stictophylla) A. leprosa is also likely to be confused with A. ausfeldii, A. dodonaeifolia or A. cognata.
