Couroupita guianensis

cannon-ball fruit


Couroupita guianensis

Aubl. 1775

pronounced: koo-roo-PEE-tuh gee-uh-NEN-siss

(Lecythidaceae — the Brazil nut family)


common name: cannon-ball tree

Couroupita is the Latinized form of the French Guiana vernacular name, kouroupitoumou; guianensis means, of course, ‘from Guiana’. This tree was named by the French pharmacist, botanist and explorer Jean Baptiste Christophore Fusée Aublet (1720–1778). In 1762 he was sent to Cayenne in French Guiana, where he assembled a vast herbarium which allowed him to prepare his Histoire des plantes de la Guiane française, published in 1775 and including almost 400 copperplate engravings.

This remarkable tree can grow up to 35 m tall, with leaves in whorls at the ends of the branches. The leaves are up to 15 cm long, simple, with serrate margins.

The flowers, which are borne only on special short stems on the main trunk, are yellow, reddish and pink, forming racemes up to 3 m long, and very fragrant.

The flowers mature into large spherical woody fruits anything up to 24 cm in diameter, looking like hanging clusters of big, rusty cannon-balls. Each fruit contains up to 300 seeds surrounded by a foetid-smelling white jelly in six segments, which oxidizes bluish-green as soon as the fruit is broken. This very heavy fruit is liable to fall without notice, so picnicking beneath one of these trees is not recommended. The foetid smell is released when the fruit breaks as it hits the ground (or anyone who is sitting or standing under the tree). The fruit is eaten by peccaries, chickens and pigs, who pass the seeds in their faeces. If the seeds have not broken open upon hitting the ground, it would seem that the peccaries are the only animals capable of breaking them open.

The cannon-ball tree is planted in tropical and subtropical botanical gardens throughout the world because of its large, beautiful and aromatic flowers, and because it is unlike any other flower a newcomer to the tropics will ever have seen. The unusual appearance of the fruits is also of interest to tourists.

The flowers, apart from their beauty, are also interesting botanically. The structure of the male part of the flower is not found in any other plant family in the world. Fertile stamens are found in a ring round the reduced style, and other stamens with sterile pollen are found located in the hood (a prolongation of the ring of stamens that arches over the ovary). The flowers have no nectar. They are visited by pollen-seeking large bees of the bumble-bee type who enter the flower with their bellies against the sterile pollen of the hood, and their heads and backs against the ring containing the fertile pollen, and, as a result of this, they are dusted with the fertile pollen on their heads and backs. In other words, the sterile pollen has been developed to serve as a reward to attract the pollinating bees to the flowers. They then transfer the fertile pollen to the flowers subsequently visited.

Although the tree is most often seen as a curiosity in botanical gardens, in its native habitat it is sometimes cut for timber. The heartwood is basically white or grey, but sometimes brownish, and the sapwood has a very similar appearance. It can be used for furniture-making.

The accompanying photographs were taken on the Cairns Esplanade, but I am told that there are some of these trees growing near the West Point Road past the end of the bitumen.


Photographs taken on Cairns Esplanade 2008
Page last updated 30th November 2018