Bursera is a genus of approximately 100 flowering trees and shrubs in the family Burseraceae — a family of which it is the type genus. Plants range considerably in stature, with some species reaching 25 metres tall, while others remain shrubby. The genus is immediately recognizable by its semi-succulent trunks and branches: the outer bark is typically yellowish to beige and often peels or flakes, while the inner bark underneath is distinctively bluish-green. Many species exude fragrant resins when the bark is cut — a characteristic shared with their relatives frankincense and myrrh in the same family.
Leaves are alternate and may be simple or once-pinnate, with three to eleven (sometimes more) leaflets arranged in opposite or sub-opposite pairs along the rachis, clustered toward the tips of branches. Stipules are absent. Flowers are small and appear before or simultaneously with the new leaves; sepals are light green to slightly reddish and triangular, while petals are white-cream to pale yellow, reflexing at maturity. Fruits are small — around 5–7 mm long — and turn purplish-green at maturity, with seeds covered by a thin orangish-red aril. Chromosome counts of 2n = 22 or 24 have been recorded.
The genus ranges across the Americas from the southern United States (Arizona, California, Florida) south through Mexico, Central America, the Caribbean, and into northern Argentina, inhabiting tropical and warm temperate forests. Western Mexico's tropical deciduous forests hold the greatest diversity of species. Bursera is not native to tropical Asia; species once attributed to it from that region have been transferred to the closely related genus Protium.
Etymology
The genus name Bursera honours Joachim Burser (1583–1639), a Danish-German botanist and physician who assembled one of the most important herbarium collections of the early 17th century. The name was established formally by Nicolaus Joseph von Jacquin and published by Carl Linnaeus in the second edition of Species Plantarum (1762), cited as Bursera Jacq. ex L.
Distribution
Bursera is an American genus, native from the southern United States — with occurrences in Arizona, California, and Florida — southward through Mexico, Central America, the Caribbean, and into northern Argentina. The centre of diversity lies in the tropical deciduous forests of western Mexico, where the greatest number of species is concentrated. The genus occupies tropical and warm temperate forest habitats; individual species such as Bursera simaruba extend across much of tropical America including Florida, the Caribbean, Brazil, Colombia, and Venezuela, where it favours dry forests and secondary growth.
Ecology
Bursera species are characteristic components of tropical dry forests and tropical deciduous forests, particularly in Mexico. They are well adapted to seasonal drought through their semi-succulent bark, which stores water, and their tendency to shed leaves during the dry season. Species such as B. simaruba also colonize secondary growth and disturbed habitats readily. The genus produces fragrant resins from bark canals — an ecological defence against herbivores and pathogens — and the fleshy, aril-bearing seeds are dispersed by birds.
Cultivation
Bursera species suited to cultivation — notably Bursera simaruba — prefer full sun and well-drained soils. Established plants are drought-resistant and generally require minimal irrigation once settled. They are suited to USDA hardiness zones 10–12, with optimum temperatures of 18–25°C and tolerance of annual rainfall ranging from 800 to 3,000 mm.
Propagation
Bursera simaruba (and likely related species) can be propagated from seed or cuttings. Seed germination rates are approximately 40% within 20 days, with seed viability lasting around 10 months. Cuttings root readily; even large stem sections of 1–3 metres in length will develop roots, making propagation from substantial cuttings a practical option.
Cultural Uses
Bursera species have been used across the Americas for millennia for resin, wood, medicine, and incense. The bark resin of Bursera simaruba — known as American elemi — has been used in varnishes and adhesives. The resin is also recorded as diaphoretic, diuretic, purgative, and vulnerary in traditional medicine, with applications against dropsy, dysentery, and yellow fever. Leaves have been used as a tea substitute.
Several Mexican Bursera species, including B. aloexylon and B. delpechiana, yield aromatic linaloe wood, a source of linalool oil historically important in perfumery. Bursera graveolens, known as palo santo ("holy wood"), is burned as incense across South America and is culturally significant in Andean and Pacific coastal traditions. Bursera species also supply caranna, a resinous gum used medicinally throughout tropical America. The wood of some species is used for veneer, plywood, furniture, and matches.
Taxonomy Notes
Bursera Jacq. ex L. (1762) is the type genus of the family Burseraceae, placed in the order Sapindales. Its type species is Bursera simaruba. GBIF records 238 descendant taxa under this genus key; other sources cite approximately 100 accepted species, reflecting the difference between total nomenclatural entries and accepted names only.
Several older genus names are now treated as synonyms of Bursera: Elaphrium Jacq. (1760), Simaruba Boehm. (1760), Evrardia Adans. (1763), Terebinthus P.Browne (1756), and Icicariba M.Gómez (1914). Species formerly assigned to Bursera from tropical Asia have been transferred to Protium, a closely related genus. Chromosome counts of 2n = 22 and 24 have been reported.
