The Dutch botanist Nikolaus Joseph von Jacquin (1727-1817) named this genus after Joachim Burser, a fellow-botanist. Burser’s life (1583-1639) antedated that of Carl Linnaeus (1707-1778). A physician in Saxony, Burser was called in 1625 to Denmark as professor in medicine and botany at the new Sorø Academy . He produced an herbarium in 25 volumes.
As for the species name, simaruba, it originates in native languages of the Caribbean, French Guiana in particular.
This genus of plants provides a textbook case of exhuberant vitaliy, of creativity even, if the meaning of the word is extended to biological species.
Mexican dry forests are a favored habitat for the Bursera genus. The sheer number of Bursera species in Mexico, nearly 100, is impressive. More than half of these species are found in just three Mexican states, Michoacán, Guerrero, and Oaxaca. In some places, as many as eight or ten species can be found in a single region.
The Bursera genus encompasses colorful trees with deep-red trunks (B. cinerea). Others are handsome big trees with red to copper bark and blue foliage (B. longipes). There are trees whose initial normal aspect with age turns into liana-like when the branches grow back on themselves, circling around and around within the crown of the tree. Such unusual branches can become several meters long but just a few centimeters in diameter (B. instabilis). There are also huge rounded shrub-like trees with large, arcing trunks that branch near the base sporting very large and fuzzy leaflets, appropriately named B. grandifolia.
As for the B. simaruba species, it appears to be the most adaptable to a diversity of climates and locations. Its range extends far outside Mexico. It is present on all the islands in the Caribbean. In Mexico, both the Atlantic and Pacific regions host populations of Bursera simaruba. In Central America, they are present on both coasts in a wide variety of habitats, from Caribbean slope rainforest to Pacific dryforest in Costa Rica.
Bursera appeared in Northwestern Mexico during the Miocene period, between 34 and 17 million years (Ma) ago. A probable cause is tectonics, the upliftng of the Sierra Madre Occidental mountain range resulted in a cooling of the climate, favorable to the establishment of dry forests. A southern lineage (peaking at 13.5 Ma) tracked the rise of the Neovolcanic axis (23–2.5 Ma). The enhanced aridity came about from global cooling and regional rain shadows.
But why so much variety, so many distinct species? The sheer diversity reflects the overall impressive diversity within the plant kingdom, with nearly 400,000 species. Which connects in turn with the equally mind-boggling diversity of the insect world, with several million (about 5.5 million ?) species. Such impressive numbers result from insect-plant warfare: insect herbivores attack plants and plants defend themselves with chemical weaponry, devised to repel and even destroy their predators. Darwinian selection is thus responsible for the appearance of novel species, plants at first, then followed by their insect consumers. Thus, the Bursera genus illustrates the struggle for life and the sheer vitality of natural forms.
To illustrate the antagonism of Bursera and insects, the case of B. schlechtendalii and chrysomelid beetles is instructive. The insects go on a rampage. The plants fight back, most effectively, with chemical weapons.
Take the case of the chrysomelid insect genus Blepharida. Its larvae feed on B. schelchtendalii leaves and seeds. The plant evolved in turn defense mechanisms. The more elaborate consists in parthenocarpy, i.e., production of seedless fruit.
The more immediate counterattack draws upon an extensive network of canals that run through the cortex and the leaves. When beetle larvae attack a leaf, the leaf fights back in squirt gun manner, releasing a burst of copal resin, rich in terpenes, very viscous. This projection can range up to 1.5 m (5 ft). The insect engulfed in it is immobilized, drowns in the secretions and dies. The counterploy by the insect is to cut the leaf veins before starting to eat a leaf, thus avoiding the lethal squirt.
Mankind has made extensive use of the Bursera resins, rich in terpenes and known as copal. The Aztecs used it as incense. For instance, an image in the Tudela codex shows a heart sacrifice performed before the altar of a deity with a ferocious look. The sacrificial priest wears black body paint. Below this scene, two worshippers carrying white incense pouches are piercing their tongues and ears with large bone awls. To their right, a ball of copal burns above an offering of paper — paper was sacred to the Mayas and Azecs, who produced it in abundance from the inner bark of fig trees and mulberry trees.