Only one species of Prosopis of the general glandulosan type truely exists in Mexico. Regardless of its geographic locality, when similar environments are compared, it is found that they have similar mesquites. The obvious limiting factor is humidity. Long-leaved mesquites may be bygone relics. Mesquites on the coast of Guerrero look like ones of southern USA, whereas those north of the mountains of the Sierra Madre del Sur in Guerrero have very small leaves with leaflets of perhaps 6 mm due to drought.