The archaeological remains of Leucaena (Fabaceae) revised

Archaeological specimens of leucaena (Fabaceae; Mimosoideae) previously pub lished (Tamaulipas, Tehuacan Valley, and Oaxaca Valley) which are housed at the Departmento de Prehistoria, Institute Nacional de Antropologia e Histo ria, Mexico City, were reexamined. Selected remains from Tehuacan were obse rved with scanning electron microscopy and ultrastructural features were co mpared to material from herbarium specimens. External epidermis near margin s of legume valves provided identification characteristics (stomata abundan ce and morphology, texture, pubescence). In Tehuncan, L. leucocephala subsp . glabrata was found in addition to two previously reported tara-L. esculen ta and L. diversifolia subsp. stenocarpa IL. pueblana). Acacia sericea, a w ild tree with edible legumes, was frequently misidentified as Leucaena. In Guild Naquitz Oaxaca, all samples reported as L. esculenta were identified as another edible, wild legume tree, Conzatia multiflora Chronology was ass igned following published reports and also for Tehuacan,; the field catalog ue. Possible use was assigned based upon evidence of chewing and insect dam age, indicating ripeness of legumes. Na direct evidence of cultivation was found. However, the presence oft. esculenta in Tehuacan (since ca. 4000-100 0 B.C.) and of L. 1. glabrata (since ca. 300 B.C.-A.D. 780) suggests their introduction there as a cultivated plant.