Parramatta wattle

Appearance

Growing with an upright habit, "Acacia parramattensis" is a tall shrub or tree ranging from 2 to 15 m in height with smooth bark that can be dark green, dark brown or black. The branchlets are more or less terete, sometimes with ridges. The tips of new growth are yellow and finely furry becoming smooth with age. The dark green and slightly rough leaves are joined to the stem by a 0.5–2 cm long petiole and are finely divided or bipinnate—that is, each leaf has 3–16 pairs of 1.5–6 cm long pinnae arising from it, and each of these pinnae has anywhere from 14 to 62 pairs of pinnules off it. Each pinnule is 2 to 7 mm long and 0.5–1 mm wide and linear or cultrate in shape.

The yellow flowers appear from November to February, occasionally as late as April. The yellow flowers are spherical and measure 4–7.5 mm in diameter. they are arranged in panicles or racemes, with 25 to 50 flowers occurring in each flower head. Flowers are followed by the development of the flat grey-black seed pods. Rough and furry when young before losing their fur, they are 2.5–11 cm long and 3.5–8 mm wide and sub-moniliform—linear in shape and slightly swollen over the spaces where the seeds are. The mature seeds are released over November to January.

"A. parramattensis" tends to flower later in the year than the similar early green wattle and black wattle.

Distribution

"Acacia parramattensis" is found in the Sydney Basin and Blue Mountains in central New South Wales, north to Yengo National Park, west to Grenfell and south to Tumut, from sea level to elevations of 900 metres. A component of dry sclerophyll forest or woodland, it is found in association with such trees as forest red gum, Sydney blue gum, mountain white gum, rough-barked apple, turpentine, or in drier locations with gossamer wattle, coast myall, or early green wattle. "A. parramattensis" is also a component of the rare and fragmented Southern Highlands Shale Woodlands community.

Habitat

"Acacia parramattensis" grows on alluvial or shale-based low- to medium-nutrient soil, often with some degree of clay content, or occasionally sandstone-based soils. It is found on lower slopes and along watercourses, as well as ridges. The annual rainfall is over 700 millimetres. It has possibly naturalised in Tasmania and other parts of New South Wales.The bark of "A. parramattensis" is thin and offers little protection from bushfire, with plants generally perishing from high intensity fires. Most above-ground growth is killed by fire, though plants with trunks thicker than 10–15 cm diameter at breast height may resprout from epicormic buds. Some plants can survive low intensity fires. "Acacia parramattensis" has a suckering habit, and can grow from basal shoots after fire, though regeneration is generally by seed after severe fires. The seed has a hard coating and remains in the soil after dropping from the seedpods. It colonises disturbed areas, and the suckers can form groves of plants. The species has a juvenile period of around five years.

The seed is consumed by the common bronzewing. The foliage serves as food for the caterpillars of the moonlight jewel, imperial hairstreak, amethyst hairstreak, Adult imperial hairstreak also visit the plant. The wood serves as food for larvae of the jewel beetle species "Melobasis nitidiventris", "Agrilus hypoleucus" and "A. australasiae". Older trees that are infested by borers in turn attract the insectivorous yellow-tailed black cockatoo. "A. parramattensis" is a host species for the mistletoe species "Amyema cambagei" and "A. pendula".

Cultural

In the Dharawal story of the Boo’kerrikin Sisters, one of the kindly sisters was turned into Acacia parramattensis. The other two sisters were turned into Acacia decurrens and Acacia parvipinnula.