Dominica Botanic Gardens
Roseau, Commonwealth of Dominica, West Indies
National Flower
© Dominica Academy of Arts and Sciences, Dec. 2004 | Home Page | Comments & Suggestions |Site Coordinator | Gardens Curator
Selected Trees and Shrubs:
Dipterix odorata; Syn.: Coumarouna odorata; Common name: Tonka Bean, Cumaru


Gernot Katzer

Plant Family: Belongs to the Fabaceae or Pea family, which includes Flame of the Forest (Butea frondosa) and Bois Kwaib (Sabinea carinalis).

Description: A large, overstory, rainforest tree; in its natural habitat sometimes to 50 m in height (160 ft) with trunk diameter to 1 m (40 in); unbuttressed cylindrical boles, clear to 18-25 m (60-80 ft); tree much smaller in secondary forests or when cultivated, as are Gardens specimens; leaves compound, alternately pinnate, overall to 20 cm long (8 in) by 8 cm wide (3 in); flowers rust colored in terminal panicle inflorescences; fruit a pulpy, egg-shaped drupe, about 6-9 cm long (2.3-3.5 in) and 3-4 cm in diameter (1.2-1.6 in), with very strong sweet odor, containing a single, fragrant, almond-shaped seed, dark gray to black, 2.5-3.5 cm long (1-1.4 in) and about 1 cm in diameter (0.4 in), called a "tonka bean", containing the anticoagulant oil, coumarin; this liberated by soaking seed/bean in alcohol (eg. rum) for 24 hours and drying, whereby a fermentation process takes place; afterwards, coumarin content of bean as high as 10%, with coumarin crystals visible under epidermis of seed.

Natural Habitat: Tropical rainforests, especially those of the Amazon basin -- in Brazil, Venezuela, the Guyanas, Peru and Colombia; best growth on well-drained gravelly or sandy soils; propagation by seed; trees begin bearing in 4 years.

Origin and Distribution: Tree native to Central and northern South America; now cultivated to some extent in many other tropical areas.

Uses: Primarily for timber - wood hard and durable; used for heavy construction and fine furniture; secondary uses - seeds high in coumarin, which has a pleasant vanilla-like odor; and after curing, seeds used for flavoring tobacco and snuff, and in perfumery and soaps; identified in 1820s, coumarin synthesized in laboratory since 1868, and also used to prepare other chemicals -- in particular anticoagulants (eg. warfarin) and rodent poison; today, natural coumarin almost completely replaced by synthetic product; use of tonka beans (which was never high), has further decreased, since coumarin suspected of being poisonous and carcinogenic, and is banned as a food additive in several countries; medicinally, Indian people of Amazon basin use bark decoction to bathe fevered patients; seeds soaked in rum and tincture used for snakebites, cuts, contusions, coughs and rheumatism, among other ailments; seed oil is dropped into ears for earaches and ear infections.

Indigenous Legends: Bean widely advertised on eBay as a potent “herb” for magical spells and love potions.

References:
Jason W. Clay & Charles R. Clement. Selected species and strategies to enhance income generation from Amazonian forests. FAO, Rome 1993 www.fao.org
Dipteryx odorata. Wood Technical Fact Sheets, USDA Forest Service, Madison, WI n.d. www2.fpl.fs.fed.us
Leslie Taylor. Cumaru (Dipteryx odorata). Tropical Plant Database, Raintree Nutrition, Carson City, NV 2005 rain-tree.com
Gernot Katzer. Tonka bean (Dipteryx odorata). Gernot Katzer’s Spice Pages. Graz, Austria 2000 www.uni-graz.at

© Dominica Academy of Arts and Sciences, Dec. 2004 | Home Page | Comments & Suggestions |Site Coordinator | Gardens Curator