Acacia spilleriana J.E.Br.
Acacia spilleriana J.E.Br.
Restricted to the North Mt Lofty Ra., S.A., from Burra Hill S to Tarlee.
Bushy, often rounded, spreading shrub 1–2 m high. Branchlets velvety, with dense, short, straight, uniform, patent hairs. New shoots densely hairy, the hairs iridescent light golden to very pale yellow or silvery white. Phyllodes elliptic to oblong-elliptic or obovate, (1.5–) 2–3 (–3.5) cm long, (0.7–) 1–2 (–2.3) cm wide, l:w = 1.5–2.5, rounded to obtuse, coriaceous, grey-green to glaucous, velvety; midrib and marginal nerves prominent; lateral nerves obscure; gland not prominent, (0.5–) 1–6 mm above pulvinus. Inflorescences 1- or 2-headed rudimentary racemes with axes 0.5–2 mm long; peduncles 1–3 cm long, stout, velvety; heads globular, 10–12 mm diam. (fresh), 30–40-flowered, golden. Flowers 5-merous; sepals irregularly c. 1/4–1/2-united. Pods oblong to narrowly oblong, to 5.5 cm long, (10–) 14–18 mm wide, coriaceous-crustaceous, blackish, pruinose, glabrous. Seeds oblique, oblong-elliptic, 5–6 mm long, subshiny, black; aril terminal, shortly clavate.
Grows on rocky hills, commonly along watercourses.
S.A.: c. 1 km from Auburn on Balaklava road, B.Copley 2395 (AD, PERTH); c. 6 km SE of Marrabel, B.Copley 3870 (AD); Burra Ck gorge, 3 km W of Worlds End, B.R.Maslin 5992B (AD, K, MEL).
A member of the ‘A. brachybotrya group’ and most similar to the more eastly distributed A. brachybotrya but distinguished by broader pods with oblique seeds, stouter and usually longer peduncles, larger flower-heads and commonly wider phyllodes with a denser indumentum. Acacia spilleriana is also similar to A. argyrophylla and A. dictyocarpa but most reliably distinguished by patent branchlet hairs and mostly broader pods with oblique seeds. Although J.H.Maiden, Forest Fl. New South Wales 6(3): 48, pl. 200F–N (1914), treated A. spilleriana as a variety of A. brachybotrya, he later considered it a distinct species in J. & Proc. Roy. Soc. New South Wales 53: 200 (1920). The status of this species deserves further attention.
Acacia sp. Wirrabara (B.R.Maslin 5999) has indumentum hairs that are appressed to subappressed, commonly antrorsely hooked to subcrisped (but sometimes straight) and phyllodes 10–25 mm long, 5–10 (–12) mm wide. Its short blackish pods with oblique seeds suggest closest affinities to A. spilleriana which is distinguished by its normally broader pods and phyllodes and/or patent branchlet hairs. Although A. sp. Wirrabara (B.R. Maslin 5999) phyllodes commonly resemble those of A. dictyocarpa and A. brachybotrya these two species have generally narrower pods with longitudinal seeds.
Acacia spilleriana was based on discordant elements. The flowering branch illustrated in the protologue best matches specimens from Burra Ck gorge in phyllode shape and size and inflorescence characters, although it is curious that the prominent indumentum is not shown. The name A. spilleriana is therefore here applied to specimens agreeing with Burra Ck gorge plants. The Wirrabara syntype is probably A. sp. Wirrabara (B.R. Maslin 5999) (see note below).
An entity of uncertain taxonomic status from S.A. (Bute to Burra and Wirrabara) that was treated as the ‘third variant’ under A. brachybotrya, B.R.Maslin in Fl. Australia 11A: 357 (2001) is now treated as A. sp. Wirrabara (B.R. Maslin 5999) and requires further attention. This entity encompasses, in part, J.E.Brown's concept of A. spilleriana. The flowering branch on MEL615097 is this variant and is possibly an isosyntype of A. spilleriana; the detached pods accompanying this specimen may not belong to this taxon as they are 12–14 mm wide and have oblique seeds. The specimens were unnamed and without locality but J.E.Brown was given as collector.
Acacia spilleriana occasionally hybridizes with A. calamifolia, e.g. c. 2.5 km from Auburn on Saddleworth rd, S.A., M.C.O'Leary 3717 (AD).
Data derived from Flora of Australia Volumes 11A (2001), 11B (2001) and 12 (1998), products of ABRS, ©Commonwealth of Australia
Revised by B.R.Maslin & M.O'Leary
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