Wednesday, 18 January 2012

Is it a tamarind? Is it an orange? No, it's...

One of the tallest trees at the rainforest edge bears fruit that look like small oranges. It belongs to family Celastraceae and represents the burial of the 'all plants that fruit at this time of the year are called tamarinds, whether they are tamarinds or not' hypothesis advanced some posts ago. The hypothesis has been dead for a while: it is about time that I put it in the ground.

This is icewood or ivorywood (Siphonodon membranaceus). Although it appears citrusy, the fruit is almost as hard as wood. The holes are emergence burrows of sawflies, which probably spend most of their lives excavating in an insect version of the Great Escape. If I look carefully, I'm sure I will find a little sawfly-sized vaulting horse and a solitary confinement cell.

Seeds are buried deep within the granular flesh. This is the sort of challenge that white-tailed rats enjoy — along with macadamias, coconuts and tinned beans — but the gnawer of this fruit seems to have given it away. I can't say I blame it. Those seeds would have to taste like chocolate...

Siphonodon membranaceus, like many other plant species here, is a Wet Tropics endemic.

Specimen data reproduced from Australia's Virtual Herbarium
with permission of the Council of Heads of Australasian Herbaria Inc.

Two other species of ivorywood are found in Australia. Siphonodon australis occurs in vine thickets and Araucaria forests from northern New South Wales to Cape York Peninsula (CYP). Siphonodon pendulus is a species of tropical eucalypt woodland from Georgetown to the tip of CYP.

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