Synonymy
Hakea salicifolia subsp. angustifolia (A.A.Ham.) W.R.Barker, Fl. Australia 17B: 393 (1999)
Hakea saligna var. angustifolia A.A.Ham., Proc. Linn. Soc. New South Wales 45: 261 (1920). T: Woronora R., Heathcote, N.S.W., Oct. 1915, A.A.Hamilton s.n.; holo: NSW.
Description
Tall, usually slender, shrub 1.6–7 m high. Branchlets with several prominent longitudinal ribs, ±deep red, lenticellate, glabrous. Leaves usually only present towards apex of branches, narrowly elliptic, 8–15 cm long, 4–7 mm wide, narrowly attenuate, usually acute, more rarely obtuse, blackened apically but scarcely mucronate, moderately appressed-sericeous with white and ferruginous hairs when young, rapidly glabrescent; young leaves darker.
Involucral buds 3 mm long, subglabrous externally. Inflorescence a single umbel of 16–28 white flowers in upper axils (possibly also on older wood in subsp. angustifolia); rachis 1–1.5 mm long; pedicels 4.5–7 mm long. Perianth 2–3.5 mm long, glabrous, glaucous; inner surface of tepals sometimes with dense glandular-verrucose covering above ovary. Pistil 6–6.5 mm long.
Fruit obliquely ovate, 2.3–3.5 cm long, 1.3–2.3 (–3) cm wide in median view, basally attenuate, with raised black pusticules or 1–5 mm high blunt and black-topped warts; beak smooth or with blunt-topped warts; horns often eroded; red-brown wood zone 2.5 mm wide. Seed 17–20 mm long.
Distribution and ecology
A rheophyte taxon confined to the river systems between Hornsby and Helensburgh in the Sydney region of N.S.W., in sand or sandstone.
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 recorded in Aug., Oct. and Dec.
Derivation of name
From angustus, Latin for narrow and folius, Latin for leaf, a reference to the particularly narrow leaves of this subspecies.
How the infraspecific taxa differ
Subsp. salicifolia and subsp. angustifolia, as the latter name suggests, differ in the width of the leaves; subsp. salicifolia has leaves 7-27 mm wide while those of subsp. angustifolia are 4-7 mm wide. Subsp. angustifolia is confined to the river systems of the Sydney region while subsp. salicifolia is much more widely spread in wet sclerophyll forest on the eastern coast line of New South Wales.
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.
H. salicifolia was treated as part of the Salicifolia group, an eastern states group characterised by their simple flat leaves, few-flowered inflorescences, glabrous pedicel and perianth and erect fruits, these markedly verrucose or pusticulate and usually with horns.
The only members of this group are H. florulenta and H. salicifolia.
Notes
This subspecies may be capable of producing new inflorescences from old rachises below the leaves, as does H. florulenta . The collection Whaite 1193 has one inflorescence formed in this fashion.
Representative specimens
N.S.W.: Cockle and Cowan Ck, Hornsby, W.F.Blakely NSW182301 (NSW); Georges R., Casula, E.F.Constable NSW47458 (NSW); Lane Cove R., Lane Cove Natl Park, M.Gray 5662 (CANB); Flat Rock Ck, near Helensburgh, T.M.Whaite 1193 (BRI, NSW).
Weblinks
Link to PlantNET treatment.
Further illustrations
I. Holliday, Hakeas. A Field and Garden Guide 188-9 (2005)