 Habit. Mt Lesueur, WA. Photo © W.R.Barker |
 Flowers and leaves. Photo © W.R.Barker |
 Fruit and leaves. Mt Lesueur, WA. Photo © W.R.Barker |
 Opened fruit and leaves. Mt Lesueur, WA. Photo © W.R.Barker |
Synonymy
Hakea megalosperma Meisn., Hooker's J. Bot. Kew Gard. Misc. 7: 117 (1855)
T: Mt Lesueur, W.A., J.Drummond 6: 194; holo: NY; iso: B, BM, CGE, G-DC, K, MEL, OXF, P; ?iso: MEL 1536077 (J.Drummond s.n.), MEL 1536181 (J.Drummond 6: 154 — 154 is probably a misprint for 194 as this number is not clear on the isotype in MEL).
An image of the NY type specimen of Drummond 194 can be seen on the New York Botanical Garden site.
Description
Erect multi-stemmed shrub, 0.45–1.2 m tall, to 2 m diam., lignotuberous. Branchlets and young leaves glabrous. Leaves narrowly obovate to obovate, 3.7–8.2 cm long, 11–27 mm wide, attenuate, entire, rounded, rarely emarginate; mucro 0.1 mm long.
Inflorescence axillary, sometimes from old wood; involucre 2–3 mm long; rachis glabrous; pedicels 3.5–4.5 mm long, glabrous. Perianth 3–4 mm long, white or pink, deep red with age, glabrous. Pistil 7–8.5 mm long.
Fruit obliquely obovate, 7–8.5 cm long, 3.5–4 cm wide, smooth, black-pusticulate; apiculum 2–7 mm long; horns 8–10 mm long. Seed obliquely elliptic, 40–60 mm long; wing encircling seed body, dark or mid-brown.
Distribution and ecology
An endangered and rare species from the Jurien Bay area of W.A. Occurs on lateritic sand plain with low heath.
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 May–June.
Derivation of name
From megalo-, Greek for large and -sperma, Greek for seed - a reference to the very large seed of this species.
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.
Relationships of this species were difficult to ascertain from the morphology and so H. megalosperma was treated within its own group, the Megalosperma group by Barker et al. (1999). Its flat leaves with obscure venation, glabrous flowers and fruits with seeds occupying most of the valve face suggest a relationship with the Prostrata group but the leaves are not toothed and the fruits are much larger and somewhat woodier than in that group and nor do they retain a green coloration or produce spines. Molecular studies by Mast, Milton & Jones of Florida State University (pers. comm. 17 March 2009) however support the suggestion of a relationship close to this group.
Notes
Bentham included H. megalosperma under ser. Pubiflorae (characterised by a pubescent perianth) even though it has a glabrous perianth.
The species is discussed further in B.Rye & S.Hopper, A Guide to the Gazetted Rare Flora of Western Australia, pp. 122–123 (1981). It is recognised as 'Vulnerable' in J.D.Briggs & J.H.Leigh, Rare or Threatened Australian Plants (1995).
Note: there may be bracts at the base of the flower pairs. Difficult to determine whether they are bracts or a vegetative bud.
Conservation status
See the current list of Hakea species gazetted in the Threatened Flora of the Australian Government's Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).
Hakea megalosperma: approved conservation advice (approved Oct. 2008).
In Western Australia denoted as Declared Rare Flora - Extant: taxa which have been adequately searched for, and are deemed to be in the wild either rare, in danger of extinction, or otherwise in need of special protection, and have been gazetted as such, following approval by the Minister for the Environment, after recommendation by the State’s Endangered Flora Consultative Committee.
Atkins, K.J. (2008). Declared Rare and Priority Flora List for
Representative specimens
W.A.: Mt Lesueur, C.A.Gardner (PERTH); 110 km N of Regans Ford, A.S.George 9317 (PERTH); 14 km W of Brand Hwy, Gairdner R., E.A.Griffin 1032 (PERTH); 15 km SE of Eneabba, E.A.Griffin 2164 (PERTH).
Weblinks
Link to FloraBase treatment of this species for WA.
Further illustrations
I. Holliday, Hakeas. A Field and Garden Guide 124-5 (2005)
J.A..Young, Hakeas of Western Australia. A Field and Identification Guide 70 (2006)