Mesquite is a common name for several plants in the genus Prosopis, which contains over 40 species of small leguminous trees. They are native to dry areas in the Americas. They have extremely long roots to seek water from very far under ground. As a legume, mesquites are one of the few sources of fixed nitrogen in the desert habitat. The trees bloom from spring to summer. They often produce fruits known as "pods". Prosopis spp. are able to grow up to tall, depending on site and climate. They are deciduous and depending on location and rainfall have either deep or shallow roots. Prosopis is considered long-lived because of the low mortality rate after the dicotyledonous stage and juveniles are also able to survive in conditions with low light and drought. The Cahuilla indigenous people of western North America were known to eat the seeds of mesquite.
History
Prosopis spp. have been in North America since the Pliocene era and their wood has been dated to 3300 yr BP. They are thought to have evolved with megafauna in the New World. The loss of North American megafauna at the end of the Pleistocene era gave way to one theory of how the Prosopis spp. were able to survive. One theory is that the loss of the megafauna allowed Prosopis spp. to use their fruit pods to attract other organisms to spread their seeds; then, with the introduction of livestock, they were able to spread into grasslands. Another is that Prosopis spp. had always been present in grasslands, but recurring fires had delayed plant and seed development before the emergence of livestock and grazing.
Etymology
The English word mesquite is borrowed from the Spanish word mezquite, which in turn was borrowed from the Nāhuatl term mizquitl.
Habitat
Mesquites grow as a small shrub in shallow soil or as tall as in deep soil with adequate moisture, and forms a rounded canopy nearly as wide. They may have one or multiple trunks with a multitude of branches. They have bipinnate leaflets of a light green to blue hue that cast a light to deep shade, depending on the species. Spikes of flowers form in spring and summer that form a flat pod of beans long. Many varieties form thorns. When cut to the ground, the tree can often recover.
Uses
Once the pod is dry, the whole pod is edible and can be ground into flour and made into bread.
Mesquite is native to the US and can be used as a type of lumber. It was a popular type of wood used by early Spaniards to build ships, but is now used most commonly for high-end rustic furniture and cabinets. Scraps and small pieces are used commonly as wood for cooking with smoke in Western, South Central American states.
Red-orange sap can be found on the branches of mesquite trees during the summer. This sap was used by those who lived in the desert for several medicinal treatments. The sap was used as a salve and spread on burns and cuts to speed up the healing process. Gargling a mixture of water and sap was used to soothe sore throats, and the same mixture was said to be able to cure upset stomachs.
As an introduced and invasive species
Prosopis spp. are different from most invasive species because they are highly invasive in both their native and introduced ranges. Their impacts on the invaded ecosystems include changes to hydrological, energy, and nutrient cycling, as well as consequences to biodiversity and primary production. Prosopis spp. density and canopy cover influence the herbaceous layer and native shrubs and are factors in the changes to the ecosystem.
In the United States, Prosopis has become the dominant woody plant on of semiarid grasslands. Although North America is its native range, due to an imbalance within this ecosystem has been able to spread rapidly. It is considered the most common and widely spread "pest" plant in Texas. An estimated 25% of Texas’ grasslands are infested and are so invaded that it is suppressing the majority of grass production. In Mexico and the US, the two most problematic species are honey mesquite (Prosopis glandulosa) and velvet mesquite (Prosopis velutina). Australia is also affected by the introduction of Prosopis spp., in particular, the P. pallida, P. glandulosa, P. velutina, and their hybrids with P. juliflora. Prosopis spp. are ranked nationally as one of the 20 most significant weeds. They now cover almost of land. Prosopis spp. were originally introduced to help with erosion because of their deep root systems.