22 March 2008

Guioa semiglauca

This is a medium sized rainforest tree, round about 18m, but can grow taller in very good conditions, with a spotted smooth grey trunk. It has rather dull, dark green, thick leathery leaves, which are blueish grey underneath, hence the name semi-glauca.

Underside of leaves

The leaves are pinnate-compound with 2 to 6 pairs of leaflets, each 4 to 8cm long, with one single leaflet at the end of the stem. The leaves are quite heavily veined, ovate to elliptical, with a soft blunt tip at the apex in adult trees.

Older Leaves

Guioa semiglauca is still fairly common in protected coastal areas in rainforests along the east coast of Australia, from about Nowra to Mackay in North Queensland.

It took me years to recognize this tree in my patch of rainforest because it blends into the background very well. I find it much easier to figure out what tree is what if I have a flower or something I can use to track it down. With this tree it was just a nondescript rather dull tree for months on end. Now that I know it I can see that it is one of the backbone trees along the creek, which no doubt hold the creek banks together, provide habitat and shelter for bird and beast and also food at the appropriate time of the year.

There is nothing about the tree that makes it stand out - until it flowers in early spring. It doesn’t flower every year but when conditions suit it can be covered in masses of small lightly perfumed flowers.

This is not one of those fly-by-night trees that flaunt their blossom for a week or so. No, this tree begins slowly and builds to a crescendo of flowers as the weeks progress. The flowers are not particularly showy, being a greeny cream and very tiny, but in a good year, there are masses of them borne in dense clusters in the leaf axils. I admit this many are rather difficult to miss, but this year has been a particularly good one for many of the trees and so there was a mass bloom. I’ll be interested to see as the years pass just how often it flowers this prolifically.

In fact if you are not paying attention, even with lots of flowers, you may not notice the flowers at all as they blend in so well with their surroundings, but if you are bee or a butterfly or moth, you know they are there. Not only do they blend in well but they flower high in the canopy of the tree which is surrounded by other thick bush making them rather hard to see.

Before I had put a name to my trees I noticed one beginning to bud on the edge of the creek. I watched the buds develop and finally open and then noticed with great interest that thousands of bees visited and feasted on the nectar.

As successive trees opened their flowers, very high in the rainforest canopy, I could tell just by the drone of the bees, that something special was happening way up high, and then it took a pair of binoculars before I was sure.

Even before the buds of the Guioa semiglauca were fully opened it was attracting dozens, perhaps hundreds, of fluttering brown and orange tiny butterflies, Hypocista metirius in early October. It was a definite meeting point.

Once the flowers finish the tree maintains interest for a little longer with the attractive seed capsules, 8 – 12 mm wide.

These are flattened with 2 -3 wing like lobes which swell to contain brown seeds covered in an orange-red aril in summer.

Now it is the turn of the birds who find the seeds very attractive. Those that are not recycled this way fall to the ground and generally germinate. These young trees are browsed by wallabies and so not many make adult trees.

Very interesting news letter

17 March 2008

ALLOCASUARINAS – Members of the Casuarinaceae

I have been seduced by a denizen of the Australian bush!

I find myself drawn to him, I admire his stunning tall and handsome bronzed good looks. It’s true his wardrobe consists only of shades of brown, but he shines and gleams like burnished copper as he gently sways with the breezes and turns first this way and then that in the autumn sunshine. He may be wearing golden brown, rusty brown, or sometimes the thick gooey amber of thick, rich honey, but always, always - he attracts attention.

Most of the time the Casuarinas and Allocasuarinas take their place in the bush very modestly - without drawing attention to themselves at all – until they flower. And then surely it is “Look at me, look at me!”

The colour consists of hundreds and hundreds of skinny, long, male “flowers”, all swaying in the breeze, sending their pollen off on a journey, hoping they will land on a female “flower”.
The male flowers are actually stamens in spikes at tips of branches, but it’s easier to refer to them as flowers.

My interest in these small trees began long ago, before I had even heard of the Casuarinaceae, when I would drive my school aged children to the station along a road lined with Allocasuarina distyla, interspersed occasionally with the very attractive Allocasuarina torulosa. Every morning and afternoon in March and April, I would remark on how beautiful they were, and every time my children would look back at me and roll their eyes in disagreement - “But Mum they’re brown” was the chorus from the back seat. To them brown was not a colour to be admired. I never could persuade them otherwise.

And so it is with other people. People are often concerned for the health of my beautiful trees. They think the trees are dying and they allow a flicker of concern to curl around the tree as they speed past on their way to somewhere else. But if you take the time to stop, hop out of your car and inspect that glorious orange/brown coloured tree you will cease to be concerned and may be won over, as I am.

This photograph is Allocasuarina torulosa

Once all members of the Casuarinaceae family were Casuarinas but they have been reclassified due to some differences in the fruit, and we have gained the rather clumsy Allocasuarina, which are distinct from the Casuarina but still remain in the Casuarinaceae family. Ah, the mysterious ways of science.

All share the jointed cylindrical branchlets which remind people of a pine tree but there is no relationship at all. The Casuarinaceae are in a group all on their own and unlike the conifers which they resemble they are true flowering plants. The Casuarinaceae family is native to Australia, southeast Asia and islands of the Pacific.

My interest in these trees was rekindled a couple of years ago when I was in the bush searching for pretty flowers to photograph. I caught sight of the little red female flowers and was amazed. Amazed because I didn’t know about them. Amazed because I had never seen them before, amazed because they had never been drawn to my attention in any book I had read on native plants.

They are very small it is true but very attractive as they cluster in numbers along the branchlets.

I have discovered that there are always some flowers to be seen, though the greatest number occur now (March, April); at the same time as the males are flowering away brilliantly.

Sometimes the female flowers are a tawny shade of bronze to match the menfolk but more often they are red. They aren’t flowers so much as tiny brush-like clusters of reddish stigmas.

Some Allocasuarina trees have both male and female on the same tree which seems a much more sensible idea to me. Much less hit and miss with the fertilization technique.

In the case of Allocasuarina distyla the male and female flowers are on different trees, generally in close proximity. It is only when the male starts to flower that you can see the difference between the two.

Of course if you get out of your car and have a look you will see that all the female trees are clustered with cones at various stages of development, and so it becomes obvious which is which.

Even without the flowers I find the cones themselves attractive. The cones aren’t large, think thumbnail size.

When the time is right the cones split open and release the seed.

Farmers are not as enamoured as I of the casuarinas because nothing much will grow beneath the trees and some maintain that they somehow poison the ground. More study needs to be undertaken to figure out what is going on but for our purposes we will just acknowledge that they may be seriously defending their patch and continue to appreciate them for their beauty.