Acacias of Australia

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Acacia monticola J.M.Black x Acacia tumida var. pilbarensis M.W.McDonald




Occurs in north-western W.A. in the vicinity of Nimingarra Ridge (near the abandoned Shay Gap township, c. 200 km E of Port Hedland).


Shapely shrubs 1.5–2.5 m high. Bark pseudo ‘Minni Ritchi’ at base of main stems (i.e. grey and peeling in irregular, narrowly oblong strips that are flat or shallowly recurved at each end, the underlying new bark light brown), grey and smooth on upper stems and branches. Branchlets glabrous or hirtellous. Phyllodes oblong-elliptic, obtuse, 3–7 cm long, 8–16 mm wide, sparsely and minutely hirtellous, aging glabrous; longitudinal nerves numerous, 3 more pronounced, minor nerves sometimes anastomosing. Inflorescences simple and also short racemes 2–12 mm long; peduncles 6–11 mm long, sparsely to densely hirtellous; spikes obloid to short cylindrical, 10–16 mm long, bright golden. Flowers 5-merous; calyx dissected for about ¼–½ its length. Pods and seeds not seen.


Flowers June–Aug.


It grows on sandplains at the base of low rocky ridges.


W.A.: c. 2 km E of Nimingarra Ridge, Shay Gap area, B.R.Maslin 8731 (MEL, PERTH).


The putative hybrid status of this entity is suggested by field observations and from a critical examination of herbarium material. In one population it occurred (at a low frequency) with the two presumed parents from which it is distinguished by its pseudo ‘Minni Ritchi’ bark, short spikes and phyllode morphology. See B.R.Maslin et al., Wattles of the Pilbara CD-ROM (2010), for further discussion.

FOA Reference

Flora of Australia Project