| Hymenaea | |
|---|---|
| Hymenaea stigonocarpa | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Rosids |
| Order: | Fabales |
| Family: | Fabaceae |
| Subfamily: | Caesalpinioideae |
| Tribe: | Detarieae |
| Genus: | Hymenaea L. |
| Type species | |
| Hymenaea courbaril L. |
|
| Species | |
|
Hymenaea aurea |
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Hymenaea L. is a genus in the flowering plant family Fabaceae (legume family). Of fourteen living species in the genus, all but one are native to the tropics of the Americas, with one additional species (Hymenaea verrucosa) on the east coast of Africa. Some authors place the African species in a separate monotypic genus, Trachylobium.[1] In the neotropics, Hymenaea is distributed through the Caribbean islands, and from southern Mexico to Brazil. Linnaeus named the genus in 1753 in Species Plantarum for Hymenaios, the Greek god of marriage ceremonies. The name is a reference to the paired leaflets.
In Colombia the trees are called algarrobo, and in Peru azúcar huayo. The Brazilian name is jatobá.
Most species of Hymenaea are large trees and they are primarily evergreen. They may grow to a height of 25 m (82 ft) and emerge above the forest canopy. Some species will grow both as tall forest trees and as smaller shrubby trees depending on their surrounding habitat. The leaves are pinnately bifoliolate, meaning that they have two leaflets attached to the sides of the petiole. The flowers grow in a panicle or corymb type of inflorescence.
The pulpy center of the fruits are edible and contain starch. The fruit is sold in local markets in the Americas. The leaves may be used to make a tea. The trees produce a dense wood used for timber in making ships and furniture. The thick bark of some species is used by indigenous people of the Amazon to make canoes. Seeds contain large amounts (40% of dry weight) of a highly viscous polysaccharide (xyloglucan) which can be used in several industrical sectors such as food, paper, cosmetic and pharmaceutical.
The trees also make hard resins that are used to manufacture varnish, especially the resin from Hymenaea courbaril (jatobá) in Brazil. The resin that is produced in Brazil is known as South American copal, and Hymenaea verrucosa is the source of the valuable Zanzibar copal. Resin may be collected from living trees, or from the soil near the place where a tree once stood. Throughout its American range, indigenous peoples use the resin for incense and as a cement. Resin from the extinct species Hymenaea protera is the source of Dominican amber and probably of most amber found in the tropics.
In the neotropical region, Hymenaea courbaril has been used as a model organism to study the effect of CO2 concentration on the rate of photosynthesis. When the concentration of CO2 is increased from some unspecified level to 720 ppm, the rate of photosynthesis increases by about 60%, and the rate of cellulose production increases by about 30%. The concentration of CO2 in the atmosphere will reach 720 ppm in the year 2100 if it continues to increase from some unspecified time to 2100 at the same rate that it was increasing at that unspecified time.
Seedling establishment is promoted by xyloglucan mobilization during development in Hymenaea courbaril. Seeds germinate after about 18 days and start xyloglucan mobilization after 45 days. This takes place for about 20 days, when photosynthesis is established and the seedling becomes independent.
One of the signs that storage mobilization is occurring is that young leaves become red due to the presence of anthocyanins.
Seedlings from the rain forest invest 70% of their carbon in the aerial parts whereas the one from savannah invests more carbon (ca.70%) on root development.
Hymenaea is a very important species in programmes of recuperation of degraded Rain Forests in the Neotropics. Regarding ecological succession, Hymenaea courbaril appears late in the process being classified as a 'late successional' or climax species.