Eucalyptus quadrangulata

White-topped Box or Coast White Box

Family: Myrtaceae

A large tree, growing to a height of 45 to 50 m, forming a lignotuber.

Found on the slopes and edges on the eastern side of the Northern and Central Tablelands in New South Wales, between Dorrigo and Scone in the north to Bundanoon and Milton in the south. There is also a disjunct population near Cunninghams Gap in south-eastern Queensland. It has a distribution of two disjunct clusters in NSW. Common around localities such as Mittagong / Bowral. Usually found on shale and basalt soils, occasionally on sandstone.

Bark is rough (box-type), greyish brown, finely tessellated / fibrous or flaky bark on the trunk and branches. Upper branches bare.

Young plants and coppice regrowth have stems that are square in cross-section and leaves that are arranged in opposite pairs and sessile with their bases surrounding the stem.

The juvenile leaves are lance-shaped, paler on the lower surface to 150 mm long and to 35 mm wide.
Adult leaves are the same shade of glossy green on both sides, lance-shaped to curved, to 190 mm long and to 22 mm wide, tapering to a petiole up to 25 mm long. The leaf margins can have a distinctive stepped-pattern which aids identification.

The flower buds are arranged in leaf axils, the individual buds usually sessile. Mature buds are oval to spindle-shaped to 7 mm long and about 3 mm wide with a conical operculum/ calyptra.
Flowering occurs from February to March and the flowers are white.

The fruit is a woody, conical capsule to 5 mm long and to 6 mm wide with the valves exserted.

In the garden

A potentially very large tree and some grandiose specimens can be found in places such as the Southern Highlands of NSW where they can grow to at least 45 m tall.

Does well in a paddock or open large garden. Has a nice form and structure. Not suited to small-medium sized residential gardens.

The leaves have a unique appearance with their stepped margins. Would make a nice specimen tree.

Eucalypts can suffer problems from, caterpillars, leaf eating beetles, psyllids and borers to name a few. In undisturbed conditions, the numbers of eucalypt-feeding insects and their predators and parasites are in balance, so that they rarely cause tree death and most trees quickly recover from attack. In a home situation nature can get out of balance.

Propagation

Eucalyptus can be propagated by seeds which is most common method or grafting.

Cuttings are difficult to start, but can be used in some species. For further information refer to: http://anpsa.org.au/APOL2007/sep07-s1.html

Other information

Eucalyptus is one of three similar genera that are commonly referred to as “eucalypts”, the others being Corymbia and Angophora.

Eucalyptus – from Greek, eu, “well” or “true” and calyptus, referring to the calyptra (καλύπτρo) or operculum, which is a bud cap or covering which covers the developing flowers. The calyptra is a fusion of petals and/or sepals and is shed when the flower opens, leaving a flower with many stamens (staminate) surrounding one female part (carpel).
quadrangulata – Latin, 4-angled, referring to the cross-section of the branchlets..

https://en.wikipedia.org/wiki/Eucalyptus
https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Eucalyptus~quadrangulata
‘Field Guide to Eucalypts Vol 1 South Eastern Australia’ M.I.H.Brooker and D.A.Kleinig. Blooming Books.

By Jeff Howes