On my recent trip to the Royal Botanic Gardens, I was delighted to see a Gymnostoma (Casuarinacea) from New Caledonia. Gymnostoma deplancheanum is restricted to the southern mountain region of the island, where it grows on metal-rich ultramafic soils.
This tree is an early coloniser after fires. It is important in fixing nitrogen and providing shade and litter for more delicate species. Its tolerance to metals means that is also useful in revegetation of mine sites.
New Caledonia is a centre of diversity for Gymnostoma, the most basal of the four genera of Casuarinaceae. Eight of the eighteen species occur on the Main Island. Although it had more species in prehistoric times, Australia now has one extant Gymnostoma —the so-called Daintree Pine (G. australianum).