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Flowers and leaves. Photo W.R.Barker.

Fruit and leaves. Photo W.R.Barker

Closed fruits. Photo W.R.Barker

Synonymy

Hakea sericea Schrad. & J.C.Wendl., Sert. Hannov. 3: 27 (1797)

T: not designated, presumably a plant grown in the Hannover Garden.

?Banksia tenuifolia Salisb., Prodr. Stirp. Chap. Allerton 50 (1796); Hakea tenuifolia (Salisb.) Britten, J. Bot. 54: 59 (1916), nom. illeg. non Dum.-Cours. (1805); H. tenuifolia var. tenuifolia Domin, Biblioth. Bot. 89: 592 (1921), p.p., nom. illeg. T: Port Jackson, N.S.W., Jac. Lee; holo: not found.

Conchium aciculare Sm. ex Vent., Jard. Malmaison 2: 111, t. 111 (1805), non Donn; Hakea acicularis (Sm. ex Vent.) Knight, Cult. Prot. 107 (1809); Banksia acicularis (Sm. ex Vent.) J.Parm., Cat. Arbr. Parm. 111 (1818). T: cultivated, Malmaison, Paris, s.d., Anon s.n., [Herb. Ventenat]; holo: G.

Conchium aciculare Donn., Hortus Cantabrig. 2nd edn (1800), nom. nud.; Hortus Cantabrig. 3rd edn, 21 (1804), nom. nud.

Conchium compressum Sm., in A.Rees, Cycl. 9, no. 5 (1807), pages unnumbered; Hakea acicularis var. smithii Endl., Gen. Pl. Suppl. 4: 85 (1848), based on C. compressum Sm. T: near Port Jackson, N.S.W., Dr White; holo: not found.

?Hakea sp. 1, E.M.Ross in T.D.Stanley & E.M.Ross, Fl. SE Queensland 2: 21 (1986).

Description

Divaricate shrub to 4 m high; lignotuber absent. Branchlets ash-white to ash-grey, densely woolly-tomentose, persistent. Leaves spreading, grooved below, 1.3–7.2 cm long, 0.7–1.3 mm wide, moderately appressed-sericeous, quickly glabrescent; apex porrect, with mucro 1–2 mm long.

Inflorescence axillary umbel of 1–6 flowers; rachis simple, 0.5–1.5 (–2.5) mm long, densely woolly-tomentose, with hairs white, ferruginous towards base. Flowers pinkish in bud, white at maturity; pedicels 2–4 mm long, moderately to densely white-villous. Perianth 2.5–4.7 mm long, glabrous. Pistil 4–7.5 mm long.

Fruit (2–) 2.5–3 (–4) cm long, (1.5–) 1.7–2.2 (–3) cm wide, coarsely rugose-reticulate, abruptly obliquely broadly beaked; horns prominent but fragile, to 3 mm long. Seed 16–31 mm long, 6–11.5 mm wide; wing 1/2 way to ±fully down one side, not or briefly down other, black; seed body flanged down particularly the pale wood side.

Distribution and ecology

Found in coastal regions and adjacent ranges from south-eastern Qld to south-eastern N.S.W. and (probably naturalised) at Anglesea, Vic.

It is also naturalised on Norfolk Is., N.S.W., in New Zealand and South Africa, where it can be a particularly troublesome weed.

Occurs in dry sclerophyll forest and heaths.

To plot an up to date distribution map based on herbarium collections for this species see Australia's Virtual Herbarium. Localities outside the native range may represent cultivated or naturalised records.

Flowering time

Flowers July–Oct.

Derivation of name

From sericeus, Latin for silky, presumably a reference to the silky shining hairs on the young branches.

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Relationships

Part of Section Hakea of Bentham (as Euhakea) and characterised by a non-conical pollen presenter, leaves without obvious venation, perianths with or without hairs and fruits with or without horns. Barker et al. (1999) recognised a number of informal morphological groups within the section.

H. sericea was treated as part of the Sericea group, a predominantly eastern states group characterised by their simple terete leaves, few-flowered inflorescences, hairy pedicels and solitary, prominently woody fruits, these often markedly verrucose or pusticulate and usually with horns.

Other members of the group are H. actites, H. constablei, H. decurrens, H. gibbosa, H. kippistiana, H. leucoptera, H. lissosperma, H. macraeana, H. macrorrhyncha, H. ochroptera and H. tephrosperma, predominantly from the eastern states of Australia.  

Notes

A particularly aggressive weed in the fynbos vegetation of South Africa. H. sericea was introduced to south Africa around the time of the first European settlement of Australia. In 1962 it was the first species to be targetted for biological control studies in South Africa (Kluge & Neser 1991). Initial searches for control agents were not particularly successful since it was the very similar appearing H. decurrens which was sampled. 

With clarification of the taxonomy of the group and sampling of true H. sericea there has been much greater success and there are currently a number of agents which have been introduced to South Africa - these include the Hakea seed-moth, Carposina autologa, and a seed-feeding weevil, Erytenna consputa . For further information about these agents, and also the Hakea gummosis fungus, Colletotrichum gloeosporioides, see the website listing the biocontrol agents against alien invasive plants in fynbos of the ARC Plant Protection Institute.  

Representative specimens

Qld: Mt Barney, C.T.White 7862 (BRI, NY). N.S.W.: Audley, near Port Hacking, S.T.Blake 19037 (BRI, NSW); Pigeon House Ra., along road from Nerriga to Nowra, c. 3.2 km E of Endrick R., R.D.Hoogland 10029 (A, B, BISH, CANB, G, K, L, NSW, P, PH, TNS, US); New North Rothbury, on road to Branxton, M.E.Phillips 357 (CANB, DNA); Nerriga, between Nerriga and Towga above The Jumps, Walker ANU1148 (CANB, NSW, K). Vic.: Anglesea, H.M.Lee 353 (AD).

Weblinks

Link to PlantNET treatment for NSW.

More photographs of this species can be seen on the Australian National Botanic Gardens site.

Ferdinand Bauer’s detailed drawing of this species as Hakea acicularis was published by Endlicher as tab. 24 in Icon. Gen. Plantarum in 1837and can be seen on the PlantSystematics.org site.

As a weed

Link to SA eFlora treatment.

 

A Category 1 plant on the Declared Weeds & Invaders list for South Africa .

Background on Needle-bushes as weeds in the fynbos vegetation of South Africa.  See notes above for the fact sheets on the biological control agents which have been introduced into South Africa.

 

A fact sheet for Hakea sericea as a weed in Portugal .

 

A fact sheet on Hakea sericea as a weed in the Bay of Plenty region of New Zealand.

 

A fact sheet about Hakea sericea as an Alert Species in Europe by the European and Mediterranean Plant Protection organization. This sheet also list the species as naturalised in France and present in Spain.

 

A recent review of efforts to eradicate this species in South Africa over the last 40 years can be found in:

Esler, K.J., van Wilgen, B.W., te Roller, K.S., Wood, A.R. & van der Merwe, J.H. A landscape-scale assessment of the long-term integrated control of an invasive shrub in South Africa. Biological Invasions 12: 211-218.

Further illustrations

 I. Holliday, Hakeas. A Field and Garden Guide 192-3 (2005)

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