Synonymy

Hakea rigida C.A.Gardner ex Haegi, Fl. Australia 17B: 395 (1999)

T: Campion, W.A., 28 Sept. 1931, C.A.Gardner 2761; holo: PERTH; iso: PERTH.

Description

Erect to spreading shrub, 0.6–2.7 m tall; root-system unknown. Branchlets densely appressed-pubescent at flowering. Leaves variable, ±terete to almost flat, linear; ±terete leaves equilaterally to compressed pentagonal in cross-section, convex to shallowly concave between angles, 3.5–14 cm long, 1–2 mm diam., sparsely appressed-pubescent, often twisted near base, with longitudinal veins 5 all around, at angles, or sometimes 9 in all in distal half with prominent veins on all faces but adaxial one; almost flat leaves ±thick, concave with 5 prominent longitudinal veins, 2 marginal and 3 on underside (venation on upper side obscure).

Inflorescence a solitary axillary umbelliform raceme, with 18–20 flowers; pedicels pink, glabrous. Perianth bright pink. Pistil 6.5–8 mm long; gland triangular-obovoid, 3 mm high.

Fruit 1 or 2 per axil, subsessile, obovate-elliptic, ±straight, 2–2.2 cm long, 1–1.2 cm wide, acuminate, scarcely beaked but with prominent readily broken apiculum. Seed obliquely ovate, 11–12 mm long, 5–6 mm wide; wing extending down both sides of body, not notched, pale brown with black streaks, black at base.

Distribution and ecology

Uncommon in the central wheatbelt and south-western interzone regions of W.A., from Lake Campion near Merredin north to Wialki and east towards Kalgoorlie. Occurs in open sand plain mallee-shrubland in sandy to gravelly soil. Known from only a few specimens.

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 Sept.–Oct.

Derivation of name

C.A.Gardner used the manuscript name H. rigida on specimens of his collection no. 2761 in PERTH, and this was adopted by Haegi in Flora of Australia 17B. It is from rigidus, Latin for rigid and is thought to be a reference to the leaves of this species.

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Relationships

Part of the Conogynoides group recognised by Bentham and characterised by a conical pollen presenter, veined leaves, glabrous perianth and fruits without horns. Barker et al. (1999) recognised a number of informal morphological groups within the section.

One of these was the Ulicina group. This group of 21 Hakea species was combined morphologically because they all have simple flat leaves or leaves which are apparently terete but when looked at in cross section are clearly angled; these angled leaves are longitudinally furrowed and often referred to as sulcate. Furthermore the group has inflorescences with 6-80 small flowers (with 3-18 mm long pistils) and erect woody fruits.

Members of the group are H. aenigma, H. carinata, H. costata, H. cygna, H. dohertyi, H. erecta, H. gilbertii, H. invaginata, H. lehmanniana, H. marginata, H. meisneriana, H. mitchellii, H. myrtoides, H. pycnoneura, H. repullulans, H. rigida, H. scoparia, H. stenocarpa, H. sulcata, H. subsulcata and H. ulicina, mostly from southern WA but also from south-eastern Australia.

The sulcate-leaved members of this group are H. gilbertii, H. invaginata, H. meisneriana, H. rigida, H. scoparia, H. sulcata and H. subsulcata.

Notes

It appears that the specimen thought by Lamont et al. (1987) to represent a needle-leaved form of H. erecta belongs to H. rigida.

Conservation status

For an earlier discussion of the conservation status of this taxon see F.H.Mollemans et al. (1993), Declared rare flora and other plants in need of special protection in the Merredin District. p. 207 (W.A. Wildlife Management Program No. 9, ANPWS, Canberra, ACT & CALM, Como, W.A.).

In Western Australia denoted as Priority Two - Poorly Known: taxa which are known from one or a few (generally <5) populations, at least some of which are not believed to be under immediate threat (i.e. not currently endangered). Such taxa are under consideration for declaration as ‘rare flora’, but are in urgent need of further survey.

Atkins, K.J. (2008). Declared Rare and Priority Flora List for Western Australia , 26 February 2008. (Dept of Environment and Conservation. Como , W.A.).

Representative specimens

W.A.: 16 km N of Warrachuppin, H.Demarz 10329 (CANB, PERTH); sand plain scrub S of Yanneymooning, P. de Rebeira 174 (PERTH); 2 km E of Wallaroo Rock, c. 70 km WNW of Coolgardie, K.Newbey 8822 (CANB, PERTH); 3.2 km NW of Wialki, G.M.Storr s.n. (PERTH 01891235).

Weblinks

Link to FloraBase treatment of this species for WA.

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Further illustrations

J.Young, Hakeas of W. Australia, Botanical District of Avon 22, 94 (1997)

I. Holliday, Hakeas. A Field and Garden Guide 180-1 (2005)

J.A..Young, Hakeas of Western Australia. A Field and Identification Guide 101 (2006)