Hura crepitans

Description

The sandbox tree can grow to 60 m in height, and up to 13.2 m in girth at 6 ft above the ground; its large ovate leaves grow to 2 ft wide. The trees are monoecious, with red, un-petaled flowers. Male flowers grow on long spikes, while female flowers grow alone in leaf axils. The trunk is covered in long, sharp spikes that secrete poisonous sap. The fruit are large, pumpkin-shaped capsules, 3 - long, 5 - diameter, with 16 carpels arranged radially. Its seeds are flattened and about 2 cm diameter. The capsules explode when ripe, splitting into segments and launching seeds at 70 m/s. One source states that ripe capsules catapult their seeds as far as 100 m. Another source states that seeds are thrown as far as 45 m from a tree, most commonly 30 m. High-speed video analysis of its exploding fruit revealed that sandbox seeds fly with backspin as opposed to topspin, which had been previously assumed. Backspin helps seeds remain oriented to minimize their drag during flight.

Habitat

This tree prefers wet soil and partial shade or partial to full sun. It is often cultivated for shade. Sandbox trees are tropical trees and prefer warmer, more humid environments.

Uses

Its wood is light enough that indigenous people used it to make canoes. Fishermen have been said to use the milky, caustic sap from this tree to poison fish. The Caribs made arrow poison from its sap. The wood is used for furniture under the name "hura". In a time when most writing pens left wet ink on the page, the trees' unripe seed capsules were sawn in half to make decorative boxes (also called pounce pots) to hold the "sand" used to dry the ink, hence the name "sandbox tree".

Extracts from this species have also been documented in herbal remedies. The seeds contain an oil that is toxic if ingested but can be made into biodiesel and soap; the starchy leftovers after extracting the oil from the seeds can be made into animal feed after cooking. date=December 2018

Gallery

File:Honolulu-GraceCooke-sandboxtree-full.JPG|Large sandbox tree in Honolulu File:Hura crepitans Vietnam.jpg|Hura crepitans in Vietnam File:Hura crepitans 03.jpg|Hura crepitans in Saint John, U.S. Virgin Islands File:Honolulu-sandboxtree-trunk.JPG|Spiny trunk of Hura crepitans File:Hura crepitans in Guanacaste, Costa Rica.JPG|Leaf of Hura crepitans File:Hura_crepitans_seed1.jpg|Hura crepitans fruit carpel File:Hura_crepitans_seed2.jpg|Hura crepitans fruit carpel, opposite side

References

References

1. "''Hura crepitans'' L.". Royal Botanic Gardens, Kew.
2. {{GRIN
3. {{EOL. 1156195. ''Hura crepitans''
4. "Factsheet – Hura crepitans (Sandbox Tree)".
5. Vogel, Steven. (March 2008). "The Flight of the Seed of Hura crepitans".
6. (1950). "The Sandbox Tree and Its Armament". Bulletin of the Torrey Botanical Club.
7. (1977). "Explosive Seed Dispersal in ''Hura crepitans'' L. (Euphorbiaceae)". New Phytologist.
8. Kingsley, Charles. (17 August 1878). "At Last, Christmas in the West Indies". The Garden.
9. (2006). "Modern Biology". [[Holt, Rinehart, and Winston]].
10. (May 1977). "Explosive Seed Dispersal in ''Hura crepitans'' L. (Euphorbiaceae)". New Phytologist.
11. (2020-08-17). "Putting a New Spin on the Flight of Jabillo Seeds". Integrative and Comparative Biology.
12. (2018-03-07). "Gyroscopic stabilization minimizes drag on Ruellia ciliatiflora seeds". Journal of the Royal Society Interface.
13. "Handbook of South American Indians". [[Smithsonian Institution]].
14. Jones, David E. (2007). "Poison Arrows: North American Indian Hunting and Warfare". [[University of Texas Press]].
15. "Hura Brasiliensis. From Materia Medica by John Henry Clarke. Homeopathy.".