Australian Tropical Rainforest Plants - Online edition

Acacia hylonoma Pedley

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Leaves and Flowers. © B. Gray
Scale bar 10mm. © CSIRO
10th leaf stage. © CSIRO
Cotyledon stage, epigeal germination. © CSIRO
Cotyledon and 1st leaf stage, epigeal germination. © CSIRO

Pedley, L. (1978) Austrobaileya 1: 214. Type: Qld, east of May Peak, Yarrabah Aboriginal Reserve, Dec. 1972, Webb & Tracey 10764; holo: BRI.

Common name

Yarrabah Wattle; Wattle


Bark usually somewhat yellowish-brown.


Leaves green, phyllodineous. Leaf blades about 8-13.5 x 0.7-1.6 cm. A gland usually present on the upper edge of the leaf blade, about 9-17 mm from the base. Veins longitudinal, anastomosing, about 4-10 veins more prominent than the rest. A small ridge normally apparent running down the leafy twigs from the base of each petiole.


Inflorescence usually consisting of two pairs of heads, peduncles about 5-8 mm long, glabrous, heads about 25-flowered. Calyx glabrous, about 1.1-1.2 mm long, eventually separating into distinct lobes. Corolla about 1.8-2 mm long, about 1.5 times as long as the calyx. Stamens about 2.5 mm long. Ovary glabrous.


Pods flat, about 9 x 1.2 cm, rather thin and papery. Seeds dull brown, longitudinally oriented in the pod, about 5 x 3.5-4 mm. Funicle brownish when dry, slightly thickened and folded but not expanded beneath the seed and not encircling the seed.


Cotyledons oblong or elliptic, about 4 mm long. First leaf pinnate, second leaf bipinnate. By the third or fourth leaf stage: leaves bipinnate, petiole often expanded. At the tenth leaf stage: leaves phyllodineous, linear, +/- falcate, glabrous, about 4-6 main parallel veins run from the base to the apex; a small gland usually present on the upper edge of the leaf blade near the junction of the leaf blade and the petiole; stipules very small, visible only with a lens; stellate hairs visible with a lens. Seed germination time 3 to 147 days.

Distribution and Ecology

Endemic to NEQ, restricted to a few localities. Altitudinal range from near sea level to 400 m. Grows in well developed lowland and upland rain forest. This species is favoured by disturbance and is a component of rain forest regrowth.

Racosperma hylonomum (Pedley) Pedley, Botanical Journal of the Linnean Society 92 : 248(1986).
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