Eucalyptus species identification (II): bark revisited

By their fruits ye shall know them (II)
More small tips on Eucalyptus Identification

Gustavo Iglesias Trabado
GIT Forestry Consulting - Consultoría y Servicios de Ingeniería Agroforestal - www.git-forestry.com

EUCALYPTOLOGICS

We have seen a previous example in EUCALYPTOLOGICS of bark features being sometimes misleading for accurate Eucalyptus species identification. In that case, different bark types were present for the same Eucalyptus species. Today we see another example, but reversed. In this case, similar bark types belonging to different Eucalyptus species (Enlarge Fig. 1).

Fig. 1: Example of "bark only" diagnosis misleading Eucalyptus species identification (Click image to enlarge)

Observation and patience might easily be the two main ideas when trying to work out which of the Australian trees is standing in front of you. And observing an Eucalyptus for species identification is a process that takes several sequential steps. But undoubtly, those organs yielding the most information tend to be their flowers and their seed bearing capsules.

Fig. 2: Urceolate and globose infrutescences of Corymbia maculata (Spotted Gum, ex Eucalyptus maculata). Compare to Eucalyptus pauciflora (Fig. 1, right).

However, the same way bark is not always enough, flowers and capsules alone can be insufficent in some cases for a foulproof botanical diagnosis, especially due to they sharing with bark both seasonal and yearly variability. The ideal sampling includes the different stages of reproductive organ maturation, from flower buds to senescent capsules, and also foliage.

Fig. 3: Example of botanical sample gathering methodology for accurate Eucalyptus species identification (Click to enlarge)

Full sampling is not always required for Eucalyptus species identification albeit the more pieces of the puzzle being observed, the more accurate botanical diagnosis is. And easier! There are several hundred different Eucalyptus taxa, species, subspecies, varieties, and hybrids to get confused with. But lacking everything else, by their fruits (and not bark) you shall know them!

Interesting links

Anthesis in Eucalyptus robusta (Swamp Mahogany) flowers.
Photography by Brian Johnston (Click image to enlarge)

Maturation stages for eucalypt fruits collected on Corymbia calophylla (Marri) trees in a single visit, showing some of the internal organs within Eucalyptus infrutescences in each phase. (Click to enlarge)

Different simultaneous stages of the reproductive cycle and eucalypt seed maturation process in a standing Snow Gum Eucalyptus tree.(Click to enlarge)


After Eucalyptus seed collection: examples of Eucalyptus seedling nursery stock for afforestation

Find a local expert to ID your Eucalyptus

If you have an unknown eucalypt around and you are able to collect and photograph samples of the key organs needed for identification, do not hesitate contacting GIT Forestry Consulting.

If you are in the USA and find it easier to post fresh samples to a local expert, you can also contact Dr. Matt Ritter, resident eucalypt hunter at the California Polytechnic State University.

Visit Cal Poly Plant Conservatory

GIT's Eucalyptology Topics

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© 2008 Gustavo Iglesias Trabado. Please contact us if you want to use all or part of this text and photography elsewhere. We like to share, but we do not like rudeness.

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Corymbia maculata: an example of ornamental bark in eucalypts

Sycamore Eucalypts: ornamental spotted patterns

Gustavo Iglesias Trabado
GIT Forestry Consulting - Consultoría y Servicios de Ingeniería Agroforestal - www.git-forestry.com - EUCALYPTOLOGICS

An interesting eucalypt species from both a timber production perspective but also an ornamental point of view, Corymbia maculata (known as Eucalyptus maculata from 1844 to 1995) sets its flower buds and later its seed capsules in panicles also known as corymbs. Individual flowers and capsules are normally grouped in 3's or 4's, but many times a pair of groups grow from the same point of the branchlet, giving appeareance of groups of 7's. Globose and urn shaped capsules of medium size normally develop in dense clusters where previously medium sized white flowers attract nectar browsing fauna that involuntarily cooperate with this eucalypt for pollination.

Urceolate and globose infrutescences of Corymbia maculata (ex Eucalyptus maculata)

The spotted gum receives its name for a relatively unusual bark type within eucalypts. "Maculata" literally means "spotted", and that is the appeareance of mature bark, showing patches of grey, brown, white and yellow that give it a ressemblance to a totally different tree, Acer pseudoplatanus, the Sycamore Maple.

Smooth, patchy, multicoloured mature bark of Corymbia maculata (ex Eucalyptus maculata)

Fibrous reddish juvenile bark of Corymbia maculata (ex Eucalyptus maculata) shedding to reveal the first patches of grey and brown underneath.

Its diverse natural habitat spreading from Eastern Victoria along New South Wales to Southern Queensland suggests variation for parameters like cold hardiness, and its altitudinal distribution from sea level to 1000 m. elevation can contribute to this thought. But it is mostly a coastal species with a relatively low tolerance to frost, so care must be put in tracing seed back to the parent trees if trying to grow it in borderline areas.

Broad lanceolate ruffled and hairy underneath juvenile leaves of Corymbia maculata (ex Eucalyptus maculata) on a two year old coppiced specimen

A vigorous and big sized tree, its best ornamental feature, bark, can be displayed at its best when planted in alleys, making sure there is room enough for symmetric crowns to develop. Individual specimens are better planted in ample gardens in order to achieve full crowns.

We include it in category EUCF (absolute minima from 0ºC to -5ºC) for safe cultivation, but suitable seed provenances from mid to high elevations in the inland ranges of Victoria or Southern NSW could show a bit higher tolerance to cold, so it could be tried with caution in the mildest part of ATL1 zone (absolute minima from -5ºC to -10ºC). In our experience it can survive temperatures as low as -7ºC, but losing its yearly growth to later resprout from lignotuber, so not easily achieving tree size. A very high amount of plant losses happens when temperatures approach -10ºC. Safe zone is then around -5ºC.

In Galicia (Northwestern Spain) it is cultivated infrequently, wich is a shame, and best specimens are always present in coastal areas corresponding to USDA Zone 9.

Interesting literature

Larmour J S, Whitfeld S J, Harwood C E, Owen J V (2000). Variation in frost tolerance and seedling morphology of the spotted gums Corymbia maculata, C. variegata, C. henryi and C. citriodora. Australian Journal of Botany 48, 445–453.

Hill, K D, Johnson, L A S (1995). Systematic studies in the eucalypts 7. A revision of the bloodwoods, genus Corymbia (Myrtaceae). Telopea 6:185–504

You can also see

ORNAMENTAL EUCALYPTUS WORLDWIDE: BARK

GIT's Eucalyptology Topics

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© 2008 Gustavo Iglesias Trabado. Please contact us if you want to use all or part of this text and photography elsewhere. We like to share, but we do not like rudeness.

Click to Read Full Story...

Click to Display Summary only...