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Eucalyptus rossii

Inland Scribbly Gum or White Gum

Family: Myrtaceae

A tree, growing to a height of around 15 to 20 m and forms a lignotuber.

It has a scattered distribution over the New South Wales tablelands and western slopes, from Tenterfield in the north to Bombala in the south and as far west as Wagga Wagga and Parkes-Peak Hill area. It is generally found only west of the Blue Mountains, growing in sandy and stony well-drained soils, typically on slopes and ridges.

Has a solitary straight trunk and a dense crown. Bark sheds in patches throughout the year and usually has the typical scribbles caused by the scribbly gum moth-larvae.

Eucalyptus spp. have simple and usually alternate adult leaves with juvenile leaves starting off opposite to alternate (disjunct). In this species, juvenile / coppicing regrowth have lanceolate or falcate leaves to 140 mm long and to 40 mm wide. Adult leaves are arranged alternately, the same shade of green-blue on both sides, lance-shaped, to 150 mm long and to 25 mm wide, tapering to a petiole to 20 mm long. This species has narrower leaves than some other scribbly gums.

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 mostly arranged in leaf axils in clusters of between five and fifteen, the individual buds on pedicels to 6 mm long. Mature buds are oval to club-shaped, to 5 mm long and to 3 mm wide with a rounded operculum / calyptra. Flowers are white and occur between September and February.

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 capsule is cup-shaped, hemispherical to spherical, to 6 mm long and to 6 mm wide with the valves near rim level. The top of the capsule is red-brown when ripe.

In the garden

Eucalyptus rossii is a very hardy and durable tree that is widely cultivated, particularly in the ACT. It would make a good feature tree on a larger block, providing good shade. It has an attractive white to grey smooth trunk. Give some room to grow as it can grow to 20 m tall. Likes a free draining soil and will tolerate a rocky soil. May grow better with some enrichment. Very suited to an open landscaped garden at the top of a hill or upper slope in full sun.

The bare grey-white trunks can make a nice contrast with lower and basal flowering shrubs or groundcovers. 

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

Eucalypts 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

Regenerates easily after fire from lignotuber, epicormic growth as well as seed bank.

There have historically been 5 scribbly gum taxa recognised in NSW (E. haemastomaE. racemosaE. rossiiE. sclerophylla and E. signata). Recent studies have lumped these taxa into 3 entities as follows:
– Eucalyptus haemastoma
– Eucalyptus racemosa subsp. racemosa
– Eucalyptus racemosa subsp. rossii

Hence, the concept of E. rossii is somewhat retained. A tip for easier identification for this species/subspecies = “is your tree west of the Great Dividing Range?” in a lot of cases. 

NSW Herbarium has not yet fully accepted the above re-classification. 

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

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).

rossii – honours the science teacher William John Clunies Ross (1850 – 1914), a fellow of the Geological Society of London in 1882, and who migrated to Australia and wrote many scientific articles on the Geology of Bathurst and other areas. Ross provided specimens for Baker and Smith who described the species.

This species is not considered to be at risk of extinction in the wild.

Field Guide to Eucalypts Vol 1 South Eastern Australia M.I.H.Brooker and D.A.Kleinig. Blooming Books.

Australian National Herbarium – Eucalyptus rossii profile page                https://www.anbg.gov.au/gnp/interns-2011/eucalyptus-rossii.html

NSW Flora Online (PlantNET) – Eucalyptus rossii profile page
https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Eucalyptus~rossii

Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.

By Jeff Howes. Editing and additional text by Dan Clarke.