Acacias of Australia

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Acacia sp. Nullagine (B.R.Maslin 4955)




Confined to the Pilbara region in north-western W.A. where known from a single collection c. 30 km N of Nullagine.


Openly branched shrub 3 m high. Bark exfoliating in a pseudo ‘Minni Ritchi’ fashion (i.e. grey and peeling in short, irregularly longitudinal plates that are flat or slightly recurved at the ends, the underlying new bark reddish). Branchlets normally glabrous. New shoots resinous, moderately to densely hairy. Stipules persistent on upper branchlets, soon deciduous, triangular, c. 1 mm long. Phyllodes narrowly oblong to slightly elliptic, narrowed at base, 4–5 (–6) cm long, 5–8 mm wide, ±obtuse and mucronate by a small, conical, hard point, glabrous or with sparse, minute, appressed to sub-erect hairs; longitudinal nerves numerous and slightly scurfy, central nerve the most prominent with a sub-prominent nerve on either side of it, anastomoses few; gland obscure, 0–1 mm above pulvinus. Inflorescences simple, 1 per axil; peduncles 1–3 mm long, densely hairy, the hairs rather coarse and patent; spikes 7–10 mm long. Flowers 5-merous; calyx divided for about ¼–1/3 its length into oblong, ciliolate lobes, the tube with ±sparse and sub-patent hairs; petals glabrous or sub-glabrous, ±obscurely 1-nerved. Pods and seeds not seen.


Grows in a low-lying area between rocky hills on rocky clay.


W.A.: 29 km N of Nullagine on Great Northern Hwy, B.R.Maslin 4955 (PERTH).


This entity was recognized by B.R.Maslin et al., Wattles of the Pilbara CD-ROM (2010) and it may be a hybrid involving A. trachycarpa and A. eriopoda. The sub-persistent stipules and bark characters suggest affinities with A. trachycarpa while the short peduncles with dense, patent hairs suggests affinities with A. eriopoda. Field observations show Acacia sp. Nullagine (B.R. Maslin 4955) and A. trachycarpa as sympatric with A. eriopoda growing nearby. However, unlike other Pilbara hybrids involving these two species (see Acacia eriopoda × trachycarpa) the phyllodes of Acacia sp. Nullagine (B.R. Maslin 4955) are not linear and do not possess an upper margin that is wider than the lower margin.

FOA Reference

Flora of Australia Project