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Delonix regia (Hook.) Raf. 1837
pronounced: dee-LON-ix REE-jah
(Fabaceae — the pea family)
subfamily: Caesalpinioideae — the cassia subfamily
common name: Poinciana
Delonix is derived from two Greek words, δηλος (délos),conspicuous, andονυξ (onux), a claw, referring to the long-clawed petals of the flower; regia comes from the Latin, and means ‘royal’; poinciana, an earlier botanical name for the genus, was named for Phillippe de Longviliers de Poincy (1583–1660), the first Lieutenant-Governor of St. Kitts, who is credited with introducing the tree into the Americas.
The poinciana, when in flower, is probably the most spectacular of all the tropical trees. It is native to Madagascar, in the West Malagasy forest, where it is an endangered species, but it is widely cultivated elsewhere, and has become naturalized in Queensland, Western Australia, and parts of the Northern Territory. There are many lining the streets of Magnetic Island.
In addition to its ornamental value, it is a useful shade tree in tropical conditions, because it usually grows to a modest height of about five metres (though it can grow as high as 12 metres) but spreads widely, and its dense foliage provides full shade. Alas, its spreading lateral roots are a hazard for mowers if it is growing near a lawn, and aged trees are susceptible to being blown over in high winds when the ground is soggy with rain.
The flowers are large, with four spreading scarlet or orange-red petals and a larger upright petal (the ‘standard’), which is slightly larger and spotted with yellow and white. There is also a naturally occurring variety, flavida, with yellow flowers. The main flowering on Magnetic Island usually starts in late November or early December, although this varies according to the amount of rain the previous wet season produced. The bipinnately compound leaves are feathery in appearance. Each leaf is between 30 and 50 cm in length, with between 20 and 40 pairs of primary leaflets, each of which is further divided into 10 to 20 pairs of secondary leaflets.
The fruits are dark brown seed pods, initially green and then turning dark brown, containing up to 40 small individual seeds. The pods are explosively dehiscent.
The poinciana is very efficient at producing seedlings. In especially dry seasons it produces increased quantities of seed pods, so that more seeds will be scattered to ensure the survival of the species. The fallen seed pod casings are quickly devoured by termites. So efficient is this process that the poinciana can become an invasive species, so prolific are its seedlings, and also partly because its dense shade and root systems inhibit the growth of other species in its shade. It has reached weed status in several parts of the island. One of these places is in the “dead end” of Magnetic Street in Picnic Bay, past the recreation camp.
The sapwood of the tree is light yellow, and the heartwood is yellowish to light brown. It is soft, heavy , coarse-grained, weak and brittle, and is not a sought-after timber. Nevertheless, it takes a good polish and is rather resistant to moisture and insects although very susceptible to attack by termites.
The larvae of several Lepidoptera use this tree as a food plant, including:
Photographs ©taken in Picnic Bay 2005-2014
Page last updated 19th March 2018