Quassia

Quassia ( or ) is a plant genus in the family Simaroubaceae. Its size is disputed; some botanists treat it as consisting of only one species, Quassia amara from tropical South America, while others treat it in a wide circumscription as a pantropical genus containing up to 40 species of trees and shrubs.

Taxonomy
The genus was first published in Carl Linnaeus's book Species Plantarum ed. 2. on page 553 in 1762.

The genus was named after a former slave from Suriname, Graman Quassi in the eighteenth century. He discovered the medicinal properties of the bark of Quassia amara.

In 1962, Dutch botanist Hans Peter Nooteboom (1934–2022) had taken a very broad view of the genus Quassia and included therein various genera including, Hannoa, Odyendyea , Pierreodendron , Samadera , Simaba  and Simarouba. Then in 2007, DNA sequencing, and phylogenetic analyses was carried out on members of the Simaroubaceae family. It found that genus Samadera was a sister to Clade V and that genus Quassia was also a sister to Clade V but they had separate lineages. This suggested the splitting up of genera Quassia again, with all Nooteboom's synonyms listed above being resurrected as independent genera. This includes Samadera indica as the accepted name for Quassia indica. The ornamental Quassia amara, which is occasionally planted in Singapore, remains in genus Quassia.

Distribution
Members of the genus are found in the Tropics throughout the world. Countries and regions where species are native include: Andaman Islands, Angola, Bangladesh, Belize, Benin, Bismarck Archipelago, Borneo, northern and northeastern Brazil, Burkina, Cabinda, Cambodia, Cameroon, Central African Republic, Chad, Colombia, Comoros, Congo, Costa Rica, El Salvador, Equatorial Guinea, Gabon, Gambia, Ghana, Guatemala, Guinea, Guinea-Bissau, Gulf of Guinea Islands, Honduras, India, Ivory Coast, Kenya, Laos, Leeward Islands, Liberia, Madagascar, Malaya, Mali, Central, Southeast and Southwest Mexico, Myanmar, New Guinea, Nicaragua, Niger, Nigeria, Northern Territory, Panamá, Philippines, Queensland, Senegal, Sierra Leone, Solomon Islands, Sri Lanka, Sudan, Sulawesi, Sumatera, Tanzania, Togo, Trinidad-Tobago, Uganda, Venezuela, Vietnam, Windward Islands, Zambia, and Zaïre.

The plant is naturalised in the following places: Cuba, Dominican Republic, Haiti, Jamaica, Jawa, and Puerto Rico.

Species
The only accepted species of the genus, by Plants of the World Online as of November 2023 is: Quassia amara L.

Although World Flora Online accepts 16 species;


 * Quassia africana (Baill.) Baill.
 * Quassia amara L.
 * Quassia arnhemensis Craven & Dunlop
 * Quassia baileyana (Oliv.) Noot.
 * Quassia bidwillii (Hook.f.) Noot.
 * Quassia borneensis Noot.
 * Quassia cedron
 * Quassia crustacea (Engl.) Noot.


 * Quassia harmandiana (Pierre ex Laness.) Noot.
 * Quassia indica (Gaertn.) Noot.
 * Quassia maiana
 * Quassia pohliana (F.Boas) Noot.
 * Quassia sanguinea Cheek & Jongkind
 * Quassia schweinfurthii (Oliv.) Noot.
 * Quassia undulata (Guill. & Perr.) D.Dietr.
 * Quassia versicolor Spreng.

There are also taxa that have not been assigned a formal status:


 * Quassia sp. 'Moonee Creek', unplaced – Australia
 * Quassia sp. 'Mount Nardi', unplaced – Australia

The genus has been verified by the United States Department of Agriculture and the Agricultural Research Service (Germplasm Resources Information Network) and they only list 6 species; Quassia amara, Quassia cedron (syn. Simaba cedron, Quassia excelsa (syn. Picrasma excelsa), Quassia indica (syn. Samadera indica ), Quassia simarouba	(syn. Simarouba amara ) and Quassia undulata.

Uses
It is the source of the quassinoids such as quassin and neo-quassin. Simalikalactone D is a quassinoid that is extracted from Quassia africana for antiviral properties.