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Potentially, a very tall tree, reaching 90 metres in some habitats. It has a sturdy straight trunk with continuous stringybark and forms a lignotuber.
It grows mainly on the borders of the NSW coastal and tablelands divisions, usually on soils of higher fertility – basalt and shale most commonly. It grows from south of Toowoomba in Queenland, through the northern tablelands / north coast of NSW, down south along the ranges and slopes, into Victoria and Tasmania, as well as into SA, usually in cooler areas with higher rainfall.
It forms a dominant component of many vegetation types in some areas, some of which can be quite scenic – such as tall wet sclerophyll forest on moist ground with basalt rocks and a moist fern, grass and forb groundlayer. It can also be found as a shorter tree in dry sclerophyll forest but usually on enriched soils (shale and volcanic).
Eucalyptus spp. have simple and usually alternate adult leaves with juvenile leaves starting off opposite to alternate (disjunct). In this species, the juvenile foliage / coppicing growth is disjunct, ovate to elliptic and glossy green.
The adult leaves are also disjunct, broad-lanceolate to 15 cm long and about 3.5 cm wide, green and glossy and concolorous. Like all stringybarks, the leaves have an oblique (uneven) leaf base.
The primary inflorescence of “eucalypts” (Angophora / Corymbia / Eucalyptus) is an umbellaster (an umbel-like cluster of flowers). In the flowers of Corymbia and Eucalyptus, the petals and sepals are fused into the distinctive calyptra / operculum (bud cap) which is shed when the flower opens (in some species, 2 bud caps (opercula) are shed). The flowers are conspicuously staminate – where many stamens are basically taking over the role of the petals, all surrounding one central carpel. In this species, the flower buds are arranged in leaf axils in umbellasters of 11 or more. Mature buds are clavate (club-shaped) to 7 mm long and 4 mm wide with a hemispherical operculum / calyptra. Flowering are white and can occur in most months.
The fruit of eucalypts are a woody capsule (commonly called ‘gum nuts’) which come in a wide variety of shapes with the top part having a sunken, flat or raised disc and with the valves inserted, disc-level, exserted to strongly exserted. In this species, the capsules are conspicuously barrel-shaped and aid considerably in identification (they are somewhat different from other NSW stringybarks). They are to 12 mm long and 11 mm wide with valves usually enclosed or to rim-level.
Not overly common in gardens and other cultivated areas, but they can be observed growing in lawns and gardens surrounding houses, as well as paddocks, in areas such as the southern highlands of NSW and highlands of Victoria. They can grow to be very large, especially in Victoria and Tasmania, so not suited to small gardens. Very useful and attractive in large gully landscapes on higher fertility soils, as well as along creeklines. They can be very grandiose when large. Excellent specimen and shade tree in a larger landscape.
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.
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.
Eucalyptus is one of three similar genera that are commonly referred to as “eucalypts”, the others being Corymbia and Angophora.
It is one of the most important Australian hardwoods. Used in furniture, pulp and construction.
The tallest known specimen is in Tasmania, at 86 metres.
Regenerates from fire from epicormic shoots and lignotuber as well as from seed bank.
It is well-known that Eucalyptus is a large and diverse genus. Between 700 and 950 known species are reported, occurring as far north as The Philippines, as well as Indonesia, New Guinea, Timor and Australia. Only 16 species reportedly occur outside Australia. They occur in all Australian states. NSW currently has about 250 species. (See this website for some detailed information: https://apps.lucidcentral.org/euclid/text/intro/learn.htm).
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).
obliqua – Latin for “oblique” referring to the uneven leaf bases. Reportedly, this was one of the first stringybarks formally described – in 1789. It is considered a poor name, as all (or most) stringybarks exhibit this feature of oblique leaf bases.
This species is not considered to be at risk of extinction in the wild.
M.I.H.Brooker and D.A.Kleinig. Field Guide to Eucalypts Vol 1 South Eastern Australia . Blooming Books.
NSW Flora Online (PlantNET) – Eucalyptus obliqua profile page
https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Eucalyptus~obliqua
EUCLID – Eucalypts of Australia – Centre for Australian National Biodiversity Research – Eucalyptus obliqua profile page https://apps.lucidcentral.org/euclid/text/entities/eucalyptus_obliqua.htm
Arcane Botanica YouTube Channel (Dan Clarke) – Eucalypt Theory Video https://www.youtube.com/watch?v=m89bALPO4uc