Leaves and inflorescences; inflorescences are often found below the leaves. Photo © W.R.Barker

Inflorescences; note the bud shape, the lateral pollen presenter and the probable new inflorescence developing above the leaf scar on the branch. Photo © W.R.Barker

Synonymy

Hakea rhombales F.Muell., Fragm. 10: 90 (1876)

T: sources of the Ashburton R., Western Australia, without date, E.Giles s.n.; syn: MEL 1537937 & MEL 1537938. (The protologue describes flowers but there are none on either of these sheets.)

Description

Bushy shrub, 0.7–2.3 m tall, at least as wide as tall; root suckering. Branchlets and young leaves appressed-pubescent, with ferruginous hairs, glabrescent. Leaves simple, 6.5–23 cm long, 1.6–1.9 mm wide; mucro 2–3 mm long.

Inflorescence erect, sometimes from old wood, with 10–16 flowers; rachis simple, 7–11 mm long, glabrous or appressed-pubescent; pedicels 5.5–6.5 mm long. Perianth 6–7.5 mm long, deep pink-red. Pistil 20–24.5 mm long; pollen presenter a ±lateral disc.

Fruit obliquely obovate, 2.2–3.5 cm long, 1.6–2.3 cm wide, black-pusticulate with a toothed crest either side of suture; apiculum 2–5 mm long; horns 1.5–5 mm long. Seed 15–20 mm long; wing broadly down one side of seed body, narrowly down other.

Distribution and ecology

Occurs from Wiluna, Western Australia, to the Petermann Ra., N.T., on scree slopes, stony ridges or sand plains between ridges, frequently associated with quartzite or with gravel in creek lines.

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 Apr.–Sept.

Derivation of name

From the Latin for rhombus, the shape which Mueller attributed to the seed wing.

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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.

Within this section 5 species were assigned to the informal Verrucosa group by Barker et al. (1999). This group is not monophyletic but is held together by the shared morphological characteristics associated with bird pollination. All species have large pink or red flowers in which the tepals remain fused, splitting to the base only between the upper pair and they have a long pistil usually with a lateral pollen presenter.

Members of the group are H. bakeriana, H. pendens, H. purpurea, H. rhombales and H. verrucosa. While two of the species are found in SW WA and two are found in eastern Australia one of them (H. rhombales) is found in central Australia.

Notes

The flowers of H. rhombales are subtended by minute bracts. They are also unusual in shape, almost forming a U-shape in bud, the apex of the bud being distinctly 4- or 8-angled. They are very unpleasantly scented.

H. rhombales featured in a special Western Australian edition of Curtis's Botanical Magazine in 2003. The account of the species is accompanied by a fine painting by Philippa Nikulinsky; this painting also appears on the front of this particular issue of the magazine.

Ref: Barker, R.M. & Barker W.R. (2003). Hakea rhombales. Curtis’s Botanical Magazine 20(2): 69-73, pl. 464.

Representative specimens

Western Australia: 58 km N of Wiluna, J.S.Beard 6558 (PERTH); 22.5 km W of Mt William Lambert, Gunbarrel Hwy, A.S.George 5458 (PERTH); SW of Warburton, Gibson Desert, A.S.George 12011 (PERTH). N.T.: 29 km E of Docker River Settlement, J.R.Maconochie 677 (DNA); Rowley R., J.R.Maconochie 1919 (DNA).

Weblinks

Link to FloraBase treatment of this species for WA.

Further illustrations

R.M.& W.R. Barker, Curtis's Botanical Magazine 20(2): 69-73, pl. 424 & cover (2003).

P.Nikulinsky & S.Hopper, Soul of the Desert 83, pl. 25 (2005)

J.A..Young, Hakeas of Western Australia. A Field and Identification Guide 100 (2006)

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