Acacia difficilis
Acacia difficilis, commonly known as river wattle, is a species of flowering plant in the family Fabaceae and is endemic to the tropical north of Australia. It is a shrub or tree with fibrous bark, elliptic to narrowly elliptic phyllodes, spikes of lemon yellow to golden yellow flowers and linear, leathery pods that more or less resemble a string of beads.
Description
Acacia difficilis is a shrub or tree tree that typically grows to a height of and has fibrous, grey to brown bark on the trunk and branches. Its branchlets are almost terete, greyish brown and densely covered with soft hairs or sometimes glabrous. The phyllodes are elliptic to narrowly elliptic,mostly long and wide, thinly leathery with five to nine more or less prominent veins and densely covered with silvery white hairs when young. The flowers are lemon yellow to golden yellow and borne in spikes long in racemes long on peduncles long. Flowering mainly occurs from May to September, and the pods are linear, straight or curved, more or less resembling a string of beads, long and wide and leathery. The seeds are oblong, long, wide and black.
Taxonomy
Acacia difficilis was first formally described in 1917 by Joseph Maiden in an appendix to Acacias of the Northern Territory edited by Alfred James Ewart and Olive Blanche Davies, collected by Gerald Freer Hill in 1916. The specific epithet means 'difficult', and "presumably refers to the difficulty the author had in distinguishing it from Acacia tumida".
Distribution
River wattle is native to the Northern Kimberley bioregion of Western Australia, the Arnhem Coast, Arnhem Plateau, Central Arnhem, Daly Basin, Darwin Coastal, Davenport Murchison Ranges, Gulf Coastal, Gulf Fall and Uplands, Gulf Plains, Mitchell Grass Downs, Ord Victoria Plain, Pine Creek, Sturt Plateau, Tiwi Cobourg and Victoria Bonaparte bioregions of the Northern Territory, and to the far north-west of Queensland. It is grows in sandy or gravelly soils, often near watercourses, and is frequently associated with Eucalyptus tetrodonta.
Conservation status
Acacia difficilis is listed as "not threatened" by the Government of Western Australia Department of Biodiversity, Conservation and Attractions, and as of "least concern" under the Territory Parks and Wildlife Conservation Act and the Queensland Government Nature Conservation Act 1992.