Eucalyptus aggregata, commonly known as black gum, is a medium-sized tree that is endemic to southeastern Australia. It has rough, flaky bark, sometimes smooth on the branches, lance-shaped leaves, green to yellow flower buds in group of seven, white flowers and more or less cup-shaped fruit. It is a component of grassy woodland, often in low-lying or swampy areas, much of which has been cleared and it is under threat.
Description
Eucalyptus aggregata grows as a medium-sized tree, reaching in height, with dark grey to black rough bark that is fibrous and flaky on the trunk and smooth whitish, cream-coloured or greyish bark on the uppermost branches. The leaves on young plants vary but are mostly elliptic to egg-shaped or broadly lance-shaped, long, wide and a slightly lighter shade of green on the lower side. The adult leaves are lance-shaped, alternately arranged along the stems and measure long by wide. They are the same colour on both surfaces. The flower buds are arranged in groups of seven on a peduncle long, the individual buds on a pedicel less than long. The buds are oval, green to yellow, long, wide with a cone-shaped or beaked operculum long. The flowers are white and appear from November to May. The fruit is cup-shaped to conical, long, wide.
Taxonomy
Eucalyptus aggregata was first formally described by Henry Deane and Joseph Maiden in 1900 from material collected at Wallerawang as the lectotype. The specific epithet is a Latin word meaning "clustered", referring to the fruit.
Distribution and habitat
Black gum is a rare species found from Capertee and Bathurst in central New South Wales, south through central and southern tablelands, with an isolated population near Woodend in Victoria. It has a very patchy and scattered distribution, as much of the land throughout its range has been cleared for agriculture. Eucalyptus aggregata grows in woodland and is associated with candlebark, ribbon gum, black sallybroad-leaved peppermint and snow gum, with a grassy understory of river tussock and silver top wallaby grass. The soil is generally poorly drained, alluvial or swampy, with the black gum growing in low-lying areas. These are also natural frost hollows, where cold air persists in the cooler months. It is found at altitudes above, where there are heavy frosts and snow in winter.
Although its soft timber is of little use, the species is versatile in that it grows in other areas where few other local species thrive, and can be a useful shade tree with its dense canopy. Its foliage can be used as fodder.
