 Habit, cultivated plant. Photo © I.Holliday |
 Typical very thick leaves, axillary inflorescences; the colour of the inflorescence is usually a less conspicuous pink . Photo © I.Holliday |
 Close-up of inflorescencs; note the shape in bud, the pollen presenter and the white inside of the flower. Photo © I.Holliday |
Synonymy
Hakea clavata Labill., Nov. Holl. Pl. 1: 31, t. 41 (1805)
Conchium clavatum (Labill.) Willd., Enum. Pl. 141 (1809). T: in terra van-Leeuwin, [Western Australia], without date, J.Labillardière s.n.; syn: B (herb. Willdenow 2476), FI n.v., G-DC (microfiche seen), P (microfiche seen), TCD.
Description
Spreading shrub, often windswept, 0.2–2 m tall, 1–2.7 m diam., lignotuberous. Branchlets and young leaves appressed-sericeous. Leaves flattened, very thick, narrowly elliptic or obovate, 2–8 cm long, 4–11 mm wide, attenuate, widening at attachment, entire, rounded; mucro 1–3.5 mm long.
Inflorescence of 60–80 flowers; involucre c. 3 mm long; rachis 7–17 mm long, tomentose; pedicels 3–6 mm long, glabrous or rarely sparsely tomentose. Perianth 3.5–6 mm long, claw pink, limb grey, white inside. Pistil c. 9 mm long; gland 0.2 mm high.
Fruit obliquely ovate or obovate, 1.5–2.5 cm long, 0.9–1 cm wide, finely rugose; horns 3–5 mm long. Seed obliquely obovate, 16 mm long; wing broadly and fully down one side of seed body, narrowly and partly down other.
Distribution and ecology
Occurs in coastal areas and islands, more rarely further inland, between Esperance and Israelite Bay in Western Australia, with a single record from Hopetoun to the west; on granite, often in windswept localities.
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.
Derivation of name
From clavatus, Latin for club-shaped or gradually thickening upwards from a tapering base, a reference to the leaf shape.
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.
A difficult species to place since H. clavata has characteristics of a number of groups and has unique leaves. It has the terminal and axillary flowers of the Varia group and also H. commutata and H. circumalata of the Strumosa group. Its non-woody fruits are more characteristic of the Microcarpa group.
Notes
Hakea clavata is notable for its very thick leaves which are elliptic in cross-section, and the large number of flowers per inflorescence. A number of fruits may develop from any one inflorescence, and these are borne on a thickened rachis.
The unique, almost succulent, leaves and non-woody fruits which are not held on the plant for many seasons, may well be an adaptation to their environment of granite outcrops where there would be little moisture in summer. The production of a larger than usual number of fruits per inflorescence, their non-woodiness and non retention on the plant would suggest greater numbers of seeds produced for dispersal each year in an environment which may seldom see fire. And even if there was to be a fire then this species has the advantage of being lignotuberous.
The flowers of H. clavata are unpleasantly scented.
Representative specimens
Western Australia: Mt Merivale, Esperance, J.S.Beard 2304 (PERTH); c. 22 km SW of Mt Ragged, A.S.George 2040 (PERTH); c. 58 km W of Point Malcolm, R.J.Hnatiuk 761178 (PERTH); NW Penin., Middle Is., Recherche Archipelago, A.S.Weston & M.E.Trudgen 8709 (PERTH); Observatory Is., A.S.Weston 9377 (PERTH).
Weblinks
Link to FloraBase treatment of this species for WA.
For further information and images of this species in the Esperance region of Western Australia see William Archer’s Hakea page in Esperance Wildflowers
More photographs of this species can be seen on the Australian National Botanic Gardens site.
Further illustrations
I. Holliday, Hakeas. A Field and Garden Guide 40-41 (2005)
J.A..Young, Hakeas of Western Australia. A Field and Identification Guide 25 (2006)