araneosa ( subfam. ), a New Species from South Australia

D. J. E. Whibley

State Herbarium of South Australia, Botanic Garden, Adelaide, S.A. 5000.

Abstract .Whibley, D. J. E. Acacia araneosa (Fabaceae subfam. Mimosoideae), a new species from South Australia. Contrib. Herb. Aust. 14: 1-7, 1976. The new species, which is known only from a restricted area in the northern Flinders Ranges, is described and illustrated. Its affinities with the species considered most closely alied, namely A. rivalis, A. harveyi, A. chrysella and A. juncifolia, are discussed.

Acacia araneosa Whibley, sp. nov. Fig. 1 Arbor parva, erecta, araneosa, 3-8 m alta; truncus simplex interdum duplex, tenuis, 4-7 cm diam.; cortex laevis, canus, in ramulis porphyreus; ramuli teretes, flexuosi, glabri, ad apicem subangulares; phyllodia tenuia, teretia, pendula, glabra, (13-)18- 35(-69) cm longa, 1-1.8 mm diam., obscure quadrinervia, sicca quadrangularia; glans inconspicua, ad extremum distale pulvini posita; inflorescentia racemosa, glabra; racemi axibus 3.5-9.5 cm longis, pedunculis 5-9, 7-lo(-18) mm longis; capitula com- pacts, globosa, aurea, 50-65(-72) florum composita; flores pentarneri, lobi calycis breves, obtusi, aurei, puberuli, ciliati, petala oblanceolata, 1.7-2 mm longa; legumen 6-15.5 cm longum, 4-6 mm latum, inter semina leviter contractum, paginis undulis glabris; semina obliqua vel longitudinalis, atra, foveolata. Typus: Hj. Eichler 19652, Nudlamutana Well, northern Flinders Ranges, South Australia; along track leading westward into the mountain; 26.x.1967 (AD 96750018, holotypus, Fig. 2; CANB, MEL, BRI, isotypi). Tree, small, erect, cobwebby in appearance, 3-8 m high (Fig. 3). Trunk slender, 4-7 crn diameter, occasionally dividing about 1 m or more above the ground into two main branches. Bark smooth, grey, reddish brown on branchlets and juvenile . Branchlets flexuose, smooth, glabrous, terete, grading to slightly angular towards the apex. Phyllodes pendulous, slender, terete, glabrous, light green, sometimes scurfy, (13-)18-35(-69) cm long, 1-1.8 mm diameter, obscurely 4-nerved, becoming almost tetragonous when dry, tips tapering to a point, often recurved, not pungent, usually turning brown, withering and readily breaking off. Gland small, orbicular, often inconspicuous, situated on the distal end of the thickened, dark brown, rugose pulvinus. Inflorescence racemose, axillary, paniculate when terminating a branch; raceme axis 3.5-9.5 cm long, glabrous; peduncles 5-9 per raceme, 7-lo(-18) mm long, 2 D. J. E. Whibley

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Fig. I. Major features of Acacia araneosa. A, tip of branch with phyllodes and inflorescences; B, flower; C, opened flower with ovary; D, stamen; Dl, bracteoles; E, transverse section of phyllode; F, flower head; G, legume; H, seed and funicle. (D. J. E. Whibley 3888: AD 97347388.) Acacia araneosa, a New Species from South Australia 3

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Fig. 2. Acacia araneosa Whibley, sp. nov. Holotype: Hj. Eichler 19652 (AD). 4 D. J. E. Whibley

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Fig. 3. A tree of Acacia araneosa c. 6 m high illustrating its habit; on top of the ranges, just north of Nudlamutana Well. Acacia araneosa, a New Species from South Australia 5

glabrous, sparsely arranged with an occasional twin pair along the axis, each subtended by a small, brown, deltoid, ciliate bract. Flower heads yellow, compact, globose, com- posed of 50-65(-72) flowers. Bracetoles c. 1-1.2 mm long, laminae peltate, golden ciliate, claws membranous, linear. Flowers 5-merous, calyx 1.4-1.6 mm long, dissected to about '/8 of its length into 5 short, inflexed, slightly thickened, obtuse, golden ciliate, puberulous lobes, tube whitish, membranous, 5-nerved; corolla 1.7-2 mm long, petals 5, free, oblanceolate, sparsely golden hairy on the acute tips, glabrous towards the base, with a central nerve; stamens numerous, filaments 2.8-3.5 mm long, anthers bilocular; ovary oblong, glabrous, stipitate, light fawn to dark reddish brown; style glabrous, borne laterally on the ovary. Legume coriaceous, stipitate, linear, 6-14.5 cm long, 0.4-0.6 cm broad, straight or slightly curved with prominent nerve-like margins, somewhat contracted between the seeds, surface undulate, glabrous, olive-green, becoming brown when mature. Seeds ovoid, black, often shiny, minutely pitted, obliquely or longitudinally placed, scarcely compressed, pleurogram fine, open towards the hilum, often bordered by a band of brownish tissue, areole c. 2-2.5 mm long, 1-1.3 mm broad. Funicle yellow to reddish brown, extending about % of the distance around the seed, folded near the point of attachment and again in the middle, ter- minating in a yellowish white or brownish, clavate aril.

Fig. 4. A dense stand of Acacia araneosa on a hillside in the ranges just north of Nudlamutana Well in association with (on right of figure) and as ground cover.

Habitat It grows on calcareous soil in dry open woodland, on hillsides and ridges in association with Eucalyptus gillii and Triodia irritans (Fig. 4), and is restricted to a 6 D. J. E. Whibley small area of the northern Flinders Ranges from Nudlamutana Well along the ranges to Arkaroola. Flowering has been observed from May to October, and fruiting during October and November. The specific epithet is derived from the cobwebby appearance of the tree, because of the mesh of long, fine branchlets and phyllodes. Further specimens seen SOUTH AUSTRALIA: Northern Flinders Ranges: Hj. Eichler 19645, c. 1 km N. of Nudlamutana Well, 26.x.1967 (AD). R. H. Kuchel 3111, Nudlamutana Well, 14.ix.1973 (AD); 3121, Arkaroola, south boundary, 14.ix.1973 (AD). F. J. Vickery & J. L. Johnson rn., 15 krn NW. of Balcanoona Homestead, 24.ix.1966 (AD). D. J. E. Whibley 2177, c. 1 km N. of Nudlamutana Well, 26.x.1967 (AD); 3888, 3889, ibid., 20.v.1973 (AD); 4111, 4119, 4120, ibid., 14.ix.1973 (AD). The following modification to the key for the South Australian species of Acacia in J. M. Black, Flora of South Australia, edn 2 (1948) p. 404, is suggested: A. Phyllodes flat, not pungent, etc. ... A. Phyllodes flat, 1-nerved, not pungent, etc. ... A. Phyllodes terete or compressed, not pungent, 1-nerved P. Trees or shrubs not resinous, branchlets terete, phyllodes with one gland only Q. Trees 3-8 m high, branchlets flexuose, phyllodes 13-69 cm long ...... A. araneosa Q. Shrubs 2-3 m high, branchlets not flexuose, phyllodes 3-12 cm long Pod moniliform ...... A. calarnifolia Pod straight-edged ...... A. euthycarpa P. Resinous shrubs, branchlets acutely angular, phyllodes usually with two glands, 4-10 cm long ...... A. gracilifolia A. Phyllodes 1-nerved, flat or sub-terete, rigid, pungent-pointed ... Taxonomic Affinities In the classification used by Bentham in the Flora Australiensis 2 (1864) 302 ff., A. araneosa would be placed in Series IV. Calamiformes, C. Uninerves. However, the well developed racemose inflorescence is not otherwise known in this group. In J. M. Black's classification in the Flora of South Australia, edn 2 (1948) 403 ff., it would key out in subsection 2. Uninerves, close to A, calamifolia. A. araneosa appears also to be closely related to several other species by floral and legume characters: A. rivalis Black, endemic in South Australia, A. harveyi Benth. and A. chlysella Maiden & Blakely, endemic in Western Australia, and all three belong to Bentham's Series VI. Uninerves, F. Racemosae. The following features of these three species distinguish them clearly from A. araneosa: shrubby habit; flattened phyllodes under 10 cm long; glands variable in position but further along the phyllodes from the pulvinus; 20-40 flowers in smaller heads; shorter, more compact racemes; pubescence on peduncles and raceme axes. A. araneosa can be distinguished from those three species by the following features: tree habit and cobwebby appearance; flexuose branchlets; long, slender, terete phyllodes; gland close to the pulvinus; 50-72 flowers in larger heads; longer more open racemes; glabrous peduncles and raceme axes. A. juncifolia Benth., which occurs in New South Wales, Queensland and the Northern Territory is also similar to A. araneosa in habit and phyllode morphology, but differs in floral and legume characters, particularly in the funicle, which is small and does not encircle the seed. Acacia araneosa, a New Species from South Australia 7

The comparative notes above are based on investigation of the specimens and study of the literature quoted below: A. rivalis J. M. Black, Trans. Roy. Soc. S. Australia 42 (1918) 173, t. 18. Typus: J. M. Black s.n.: northern Flinders Ranges, near Hawker; 18.x.1917 (AD 97522274, holotype). Further specimens examined: R. H. Kuchel 2965, northern Flinders Ranges, Arkaroola, 18.ix.1971 (AD). D. J. E. Whihley 2172, northern Flinders Ranges, 1 km N. of Nudlamutana Well, 26.x.1967 (AD); 4109, northern Flinders Ranges, 30 km S. of Balcanoona, 13.ix.1973 (AD). A. harveyi Benth., F1. Austral. 2 (1864) 368. Syntypi: 'Between King George's Sound and Cape Riche, Harvey (in flower), Dmmmond, 4th Co1l.n. 130 (in fruit).' (n.v.). Bentham, Revision of the suborder Mimoseae. Trans. Lin. Soc. 30 (1874) 471. F. von Mueller, Icon. Austral. Acacia, decade 5 (1887) 8. A. chrysella Maiden & Blakely, J. Roy. Soc. W. Australia 13 (1927) 16. Typus: E Stoward 83: 1 mile from Merredin State Farm; ii.1917 (n.v.). Specimens examined: A. Ashby 4469, N. of Narembeen on Merredin road, v.1972 (AD). B. R Maslin 1757, c. 5 km NNE. of Korbel, between Merredin and Bruce Rock, 3.viii.1971 (AD). A. juncifolia Benth., London. J. Bot. 1 (1842) 341. Syntypi: 'Interior of N. S. Wales, Cunningham, Fraser, Mitchell.' (n.v.). Bentham, Revision of the suborder Mimoseae. Trans. Linn. Soc. 30 (1874) 456. F. von Mueller, Icon. Austral Acacia, decade 2 (1887) 8. Specimens examined: A. Dietrich s.n., Queensland, Brisbane River, 1863-1865 (AD 37324015). M. Lazarides 6952, Queensland, 20 km S. of Cracow Township, 10.vii.1963 (AD).

ACKNOWLEDGMENTS I am grateful to Mr J. L. Johnson (formerly Chairman of the South Australian Pastoral Board) for drawing attention to this Acacia, and to Mr F. J. Vickery for pointing out its locality in such detail that good material could subsequently be collected without difficulty. In addition, my sincere thanks are expressed to Mr B. R. Maslin, Western Australian Herbarium (PERTH), for his comments, and for information on the Western Australian ; Mr J. Carrick for the latin diagnosis; Mr L. Dutkiewicz for the preparation of the illustrations; and members of staff of the State Herbarium of South Australia (AD) for assistance during the preparation of this paper.