Citation: J. R. Maconochie, J. Adelaide Bot. Gard. 1 (3): 183 (1978).

Derivation: olgana—refers to Mt Olga (N.T.) where the type specimen was collected by R. Hill and T. R. N. Lothian.

Synonymy: Racosperma olganum (Maconochie)Pedley, Bot. J. Linn. Soc.(London), 92:249 (1986). Rounded, spreading shrubs or small trees l-5 m high, single-stemmed or dividing at ground level into a number of thin willowy ascending stems; bark rough, grey-brown, slightly fissured.

Common name: None

Description:
Phyllodes linear-lanceolate, 6-15 cm long 3-7 mm broad, slightly curved to falcate, young phyllodes golden pubescent but becoming glabrous when mature, numerous fine longitudinal veins but the central one normally slightly more prominent than the rest, margins sometimes reddish, vein-like and resinous, apex acute more or less uncinate; glands small near base.

Inflorescences simple, 1-2 per axil, sessile; spikes rather dense becoming interrupted when mature, bright yellow; receptacles with a prominent yellow silky pubescence; flowers 5-merous.

Legumes linear, 6-10 cm long, 5-6 mm broad, straight or curved, raised over seeds, quite hairy when young but almost glabrous when mature, margins thickened straight or slightly constricted between seeds. Seeds longitudinal in legume, ellipsoid; funicle with 1-2 folds beneath the seed.

Distribution:  So far only found in the Birksgate and Everard Ranges in the far North-Western region. The species often forms small thickets in tall shrubland or low woodland, associated with Eucalyptus camaldulensis, E. intertexta and Triodia basedowii. Soils; neutral red earths. Rainfall ca. 200 mm. Also N.T. Flowering time: May — August.

SA Distribution Map based on current data relating to specimens held in the State Herbarium of South Australia

Biology: No text

Related taxa: Closely related to A. doratoxylon which has longer phyllodes without the reddish margins and occurs only in N.S.W. The description of A. signata by J. M. Black, FI.S. Aust. Pt.2. 425 (1948) is A. olgana. Acacia signata is endemic to W.Aust.

Taxonomic notes: Shurcliff (1986) indicated that the seed of A. olgana is eaten by birds in the far north-west of South Australia but did not say which species are involved.

Cultivation: Recommended for ornamental planting in rocky areas with sandy well drained soil. Medium growth rate.

Author: Not yet available

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