earleaf acacia USDA PLANTS SYMBOL: ACAU
Acacia auriculiformis A. Cunningham ex Benth.
Synonym(s): auri, blackwattle, Darwin black wattle, Papuan wattle, tuhkehn pweimau

Appearance
Acacia auriculiformis is a fast-growing, crooked, gnarly tree in the family Fabaceae. It is an evergreen tree ranging from 65 ft. (20 m) tall. It has a compact spread and is often multi-stemmed. The gray-white bark often shows vertical fissures. It has no thorns. The roots normally spread only shallowly. The young growth is usually glaucous. The leaf litter of Acacia auriculiformis is thought to be allelopathic.
Foliage
The leaves are alternate, simple and reduced to phyllodes (flattened leaf stalks). These blade-like leaves are slightly curved and range from 5-8 in. (11-20 cm) long. Leaves have 3-7 main parallel veins and a marginal gland near the base. The leaf surfaces are dark green.
Flowers
The flowers are held in loose, yellow-orange spikes in the leaf axils or in clusters of spikes at stem tips. Acacia auriculiformis flowers are mimosa-like, with many free stamens.
Fruit
An Acacia auriculiformis tree can produce about 47,000 seeds a year. The fruits are flat, oblong pods. Pods become twisted as they mature and then split to reveal flat black seeds. The seeds are attached by orange, string like arils.
Ecological Threat
Acacia auriculiformis is now common in disturbed areas. It has also invaded pinelands, scrub, and hammocks. Significant populations have been discovered in the globally imperiled pine rocklands of Dade County (M. McMahon, Biological and Environmental Consulting, personal observations). Acacia auriculiformis can displace native vegetation and shade out native plants. It is adapted to nutrient-poor soils in humid tropics and is fire adapted.

Identification, Biology, Control and Management Resources