Acacia spooneri O'Leary
Acacia spooneri O'Leary
Known from two disjunct areas 150 km apart in the Flinders Ra., S.A. It occurs in the Flinders Ra. Natl Park (at Brachina Gorge and Wilpena Pound) further S at Nectar Brook on the Winninowie Ra., SE of Port Augusta.
Slender shrub or tree to 4 m high, with a spindly, open habit, normally single-stemmed. Branchlets reddish brown, glabrous. Phyllodes narrowly elliptic to oblanceolate or obovate, (2.2–) 2.5–7 (–10.2) cm long, 6–22 (–26) mm wide, size variable even on a single branch, obtuse to acute, coriaceous to thinly coriaceous, pale green to glaucous, glabrous; midrib central to slightly excentric, prominent; lateral nerves clearly visible; gland 1 or 2, the lowermost 0–18 mm above pulvinus. Inflorescences racemose; raceme axes 30–75 (–110) mm long, glabrous; peduncles 3–13 mm long, slender, glabrous; heads globular, 20–40-flowered, light- to mid-golden. Flowers 5-merous; sepals united almost to their apices. Pods linear to narrowly oblong, to 8 cm long, (4–) 5–8 (–9) mm wide, firmly chartaceous to thinly coriaceous, glabrous. Seeds longitudinal, oblong to elliptic, 4–5 mm long, slightly shiny, dark brown to black; funicle encircling seed in a double fold, brittle, dark reddish to black; aril clavate.
Flowers throughout the year with a peak in May and Aug.
Grows on rocky ridgetops in Callitris pine and mallee communities over Triodia grassland.
S.A.: nr The Guardians, Brachina Gorge, E.N.S.Jackson 165 (AD); Wilpena Pound Range, L.Haegi 2765 (BRI, CORD, RSA); Nectar Brook Range, M.C.O’Leary 2691 (AD).
A member of the ‘A. microboytra group’, most closely related to A. wattsiana and A. quornensis, both of which are most readily distinguished from A. spooneri by their fewer-flowered heads on shorter racemes and their bushy, multi-stemmed growth forms; there are also habitat differences, see M.C.O’Leary, J. Adelaide Bot. Gard. 20: 14 (2002), for further discussion.
This species was referred to as ‘a variant of uncertain rank’ under A. wattsiana by B.R.Maslin in Fl. Australia 11A: 267 (2001).
Data derived from Flora of Australia Volumes 11A (2001), 11B (2001) and 12 (1998), products of ABRS, ©Commonwealth of Australia
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