WATTLE

Acacias of Australia

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Acacia pentadenia subsp. syntoma J.E.Reid, Ward.-Johnson & Maslin

Common Name

False Karri Wattle

Family

Fabaceae

Distribution

Restricted to the north, east and north-east of Walpole in south-west W.A. in mostly Jarrah-Marri (Eucalyptus marginata-Corymbia calophylla) open forest and woodland.

Description

Shrub 0.5-1.5 m high. Pinnae 2-3 pairs; rachis 7-30 mm long; pinnules flat or shallowly concave, with margins and apex often slightly recurved, 1-2.5 (-4) mm long; gland at rachis base 0–6 mm below each pair of pinnae, absent from petiole. Inflorescences 1-2-headed racemes, 1-4 heads per axil; raceme axes 0.5-1.5 mm long; peduncles 3-7 (-8) mm long; heads pale or bright yellow.

Phenology

Flowers Aug.-Oct.; flowering commences 1-2 months earlier than in subsp. pentadenia.

Habitat

It grows on sandy/gravelly pale-coloured or yellow duplex soils on low rises, hills and ridges with granitic or sedimentary substrates.

Specimens

W.A.: Granite Peaks camp site, off Mitchell Rd, T.D.Macfarlane & A.R.Annels ARA 4465 (PERTH); 3.6 km W of Nicol Rd/Thomson Rd intersection, 40 m N of Nicol Rd, C.McChesney & C.Day W 16.1 (PERTH); 3.7 km N of corner of Break Rd and Nornalup Rd, along Nornalup Rd, G.Wardell-Johnson 16/08 (PERTH).

Notes

This subspecies was referred to by B.R.Maslin, Fl. Australia 11B: 402 (2001) as a variant of A. pentadenia having a stunted growth form and smaller than normal pinnules with reflexed tips.

Differs most obviously from subsp. pentadenia by its generally fewer pinnae, shorter leaflets, shorter peduncles and fewer heads per leaf axil. Although no single morphological attribute distinguishes subsp. syntoma from subsp. pentadenia, a combination of these vegetative and floral characters normally enable the two taxa to be reliably separated, see J.E.Reid et al., Nuytsia 19: 251 (2009) for discussion.

FOA Reference

Flora of Australia Project

Author

Revised by B.R.Maslin & J.Reid