Hakea recurva Meisn. subsp. arida (Diels) W.R.Barker & R.M.Barker, Fl. Australia 17B: 394 (1999)
Hakea arida Diels, Bot. Jahrb. Syst. 35: 162 (1904). T: Yalgarn and Murchison goldfields, July 1901, E.Pritzel 437; syn: B, BM, BR, E, G, G-DC, L, MEL, MO, NSW, PERTH p.p.; Murchison goldfields west of Cue, July 1901, L.Diels 3284; syn: B; in distr. Irwin pr. Mingenew, Sept., L.Diels 6022; syn: not located.
Erect shrub, 1–5 m tall, non-lignotuberous. Branchlets sparsely appressed-sericeous or tomentose, quickly glabrescent, glaucous. Leaves terete, straight, erect, 2.5–4 (–5.5) cm long, 1.2–1.6 mm wide, rigid, not grooved, sparsely appressed-sericeous, quickly glabrescent; mucro 2.8–4.5 mm long. Involucre 2–3.5 mm long; bracts reddish with pale brown rounded rim, usually glabrous, rarely pubescent.
Inflorescence with 20–40 flowers; rachis 1.5–3.5 mm long, villous, with white, cream-yellow or pale brown hairs; pedicels 4.5–8 mm long, glabrous, glaucous. Perianth 2.7–3 mm long, cream, white, or yellow, ?pink in bud, glabrous, glaucous or not. Pistil 7-8.5 mm long; gland 0.2 mm high.
Fruit obliquely ovate, 1.7–2.3 cm long, 0.7–1 cm wide, smooth, not apiculate; beak short and broad; horns obscure but apex always blackened. Seed c. 15 mm long; wing extending fully down one side of seed body.
Distribution and ecology
Occurs in inland areas of Western Australia from Mt Augustus south to Wubin. Recorded from sandstone slopes, from floodout areas and from red clay with quartzite and laterite.
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 aridus, Latin for dry, a reference to habitat of this species in the drier regions of WA.
How the infraspecific taxa differ
Subspecies arida and subsp. recurva differ in leaf length, width and orientation, involucral bud characters and gland size (see key below).
There are specimens in which these characters break down (e.g. the PERTH collections of Blackall s.n. from Bardoc have the leaf length and width of subsp. arida but the gland size and involucral bud characteristics of subsp. recurva), and so the two taxa have been reduced to subspecies. Some specimens with narrower leaves than the normal 2–3.2 mm wide for subsp. recurva also have a gland size intermediate between the two taxa (0.5–0.7 mm high) and further work is required on the complex before an understanding of the variation can be achieved.
Key to subspecies of H. recurva
Leaves 5–12 cm long, 2–3.2 mm wide; involucre 4–7.5 mm long, pubescent, the bracts pale with darker acuminate rim; pedicels 8–13 mm long; gland 0.8–1 mm high
Leaves usually to 4 cm long, 1.2–1.6 mm wide; involucre 2–3.5 mm long, glabrous, the bracts reddish with pale brown rounded rim; pedicels 4.5–8 mm long; gland 0.2 mm high
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.
The Microcarpa group all share the characteristics of needle leaves, oblique pollen presenter and non-woody, beaked, and sometimes horned, fruits which are not retained for any length of time on the bushes.
Unless flowers are present, distinction of H. recurva from many of the simple needle-leaved species may well prove difficult, particularly when dealing with subsp. arida.
Fruit are very quickly lost in this species and are rarely to be found on herbarium collections.
Subsp. arida has been confused in the past with H. commutata which can be distinguished by its leaves all pointing in the one direction, both terminal and axillary inflorescences and woody, non-recurving fruit which persist on the bush. It is also easily confused with H. preissii (distinguished by its pubescent flowers, horned, non-recurving fruit which persist on the bushes and by the occasional apically divided leaves), H. leucoptera and H. kippistiana ; the latter two species can be distinguished by their persistent woody fruit and by the longer rachis in H. leucoptera and the ferruginous rachis in H. kippistiana.
Western Australia: 35 km S of Moorarie HS, on road to Mileura, T.E.H.Aplin 2506 (PERTH); between Mt Magnet and Cue, C.A.Gardner & W.Blackall 74 (PERTH); 86 km N of Mullewa, J.W.Green 1573 (PERTH).
Link to FloraBase treatment of this species for WA.
I. Holliday, Hakeas. A Field and Garden Guide 176-7 (2005)
J.A..Young, Hakeas of Western Australia. A Field and Identification Guide 98 (2006)