Acacia tenuispica Maslin, Nuytsia 4: 376; 377, fig. 5 & 379, fig. 6 (1983)
Openly branched, obconic, glabrous, variably resinous shrub to 4 m high, sometimes a tree to 6 m high. Branchlets rather prominently ribbed, angled towards apices, variably tuberculate. Phyllodes asymmetrically narrowly elliptic, straight but sometimes shallowly recurved at apices, mostly 4–7 cm long, 6–16 mm wide, commonly acute, mucronate, thin, often drying brownish, sparsely tuberculate, with numerous subdistant nerves, of which 3–5 slightly more pronounced than the intervening venules, and with anastomoses few or absent; glands 2–3, not prominent, lowermost 0–1 mm above pulvinus, uppermost at base of mucro. Inflorescences simple, 2 per axil; spikes 1.5–4.5 cm long, narrow, golden; peduncles 1.5–3 mm long. Flowers 5-merous; sepals free. Pods narrowly oblong, narrowed at base, to 7.5 cm long, 6–8 mm wide, woody, red-brown, finely obliquely nerved, dehiscing elastically from apex; margins narrowly winged with wing c. 2 mm wide. Seeds oblique, elliptic, 4–4.5 mm long, somewhat shiny, brown; funicle/aril narrowly turbinate.
Occurs in the Kimberley region of northern W.A., at the Prince Regent R. and E of Walcott Inlet (where it is seemingly uncommon) and the Drysdale R. area (where it is common). Grows most commonly on sandstone in Eucalyptus woodland.
The carpological characters, narrow spikes and free sepals relate A. tenuispica to A. richardsii (which has shorter, mostly 2-nerved, reticulately nerved phyllodes), A. conjunctifolia (which has shorter, clustered phyllodes) and A. gonocarpa (which has narrower, linear phyllodes and prominently winged pods). Acacia lentiginea and A. kimberleyensis seem to be related to this group, as does the ‘Minni Ritchi’ species, A. delibrata .
A variant of uncertain rank is known from a single collection from the Prince Regent R. area, viz . 15 km E of King Cascade, K.F.Kenneally 10537 & P.P.M.Hyland (PERTH). This specimen resembles A. tenuispica in phyllode shape and size and short peduncles, but has the distinctive 2-nerved, reticulately nerved phyllodes and resin-ribbed branchlets of A. richardsii . Although these characters suggest that the specimen represents a hybrid, A. richardsii is not known to occur in the Prince Regent R. area and A. tenuispica is apparently uncommon there.
Type of accepted name
Kalumburu Mission, c. 4 km N of the Mission buildings, W.A., 30 Jan. 1982, B.R.Maslin 5151 ; holo: PERTH; iso: CANB, K.
B.R.Maslin, op. cit . 377, fig. 5.
W.A.: Drysdale R. Natl Park, S.J.Forbes 2322 (BRI, MEL, PERTH); Blyxa Ck, Prince Regent R. Reserve [Natl Park], A.S.George 12492 (BRI, PERTH); 2 km E of junction of Charnley & Calder Rivers, A.V.Milewski 224 (PERTH).