Plant of the Month - Scribbly Gums

Plant of the Month: Scribbly Gums

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POM-Scribbly-gums

“The Gumnut Strike”. May Gibbs. Snugglepot and Cuddlepie.

“They were surprised to see an Editor writing all about them in his newspaper.  Gumnut Editors generally write backwards because they say it takes longer to read it that way, and people think they are getting more news.”

May Gibbs. Snugglepot and Cuddlepie meet Mr Lizard.

One of the icons of the Australian bush are the Scribbly Gums, the scribbles being portrayed as mysterious indecipherable writings in books and poems from numerous authors including May Gibbs and Judith Wright

The gum-tree stands by the spring/ I peeled its splitting bark/ And found the written track/ Of a life I could not read.

                       Judith Wright. Scribbly Gum.

A little less romantic is the scientific explanation for how the scribbles appear in the barks of some of our Eucalyptus species.  The scribbles are made by the larvae of over a dozen species of moth.

Moths of the Ogmograptis genus lay their eggs onto select Eucalypts where the larvae hatch and dig down till they hit the layer which will become next year’s outer bark, turn a right angle and burrow along eventually turning around and going back though the soft bark which had regrown after their first munch through eventually emerging, making their way to the ground where they pupate.

The Ogmograptus moths are selective to which Eucalypts they use and presence of scribbles is often used as an identification feature (although they’re not always present). The Hunter region has five “Scribbly Gums”

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Scribbles (image Marianne Horak)

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Eucalyptus pauciflora leaf.

Key to the Hunter’s Scribbly Gums

  1. Leaves with one prominent midvein and reticulate venation                          2

1*  Leaves with sub parallel venation, generally found at over 1,000m altitude (Barrington & Coolah Tops) tree to 20m high (higher in Coolah Tops). 

Eucalyptus pauciflora                   

White Sally/Snow Gum

  1. Juvenile leaves ovate, adult leaves 1.5-4cm wide, coastal, generally south from Lake Macquarie

Eucalyptus haemastoma              

Broad-leaved Scribbly Gum

2* Juvenile leaves broad lanceolate                                                                3

  1. Adult leaves 2-3cm cm wide, tree to 25m, coastal sandy, often swampy area north from Morisset.

                                                           Eucalyptus signata                Scribbly Gum

3* Adult leaves 1.5cm wide or less                                                            4

 

  1. Found in sandstone areas in the Upper Hunter Local Government Area, tree to 20m, adult leaves narrow lanceolate – lanceolate, grey green, dull, 8-15cm long, 0.8-1.3cm wide

Eucalyptus rossii                    Inland Scribbly Gum

4* Singleton Local Government area and east,  tree to 15m tall, adult leaves narrow lanceolate 7-15cm long, 1-1.5cm wide

Eucalyptus racemosa                   

Narrow-leaved Scribbly Gum/ Snappy Gum