Ñuu Savi (`Sacred Rain's collectivity'), the Mixtec people of southern Mexico, had createdsome of the most complex polities in the continent at the time of European contact. Fivehundred years later, they remain cohesive, culturally distinct communities, as increasingnumbers of individuals and families migrate to northern Mexico and the US for work in theagricultural and service sectors. In 2005, the Mexican Federal Government reported there weremore than 446,000 speakers of Tu'un Savi (`Sacred Rain's word,' the Mixtec languages) fiveyears of age and older, 322,000 of them still living in 1551 settlements within their historichomeland; an additional 100,000 to 200,000 are estimated to reside in the US.The term Mixtec, derived from the Náhuatl mixte:cah (`cloud-people'), has been consideredby different authors to encompass between 12 and 52 mutually unintelligible languages, inaddition to numerous dialects. According to the Summer Institute of Linguistics' Ethnologue,it is the second most diversified group of languages in the Americas, after Zapotec. TheInstituto Nacional de Lenguas Indígenas, however, recognizes 81 variants of Mixtec, makingit the most diversified language group in Mexico following official criteria. The internalvariation of Mixtec and its geographic proximity to three related groups (Cuicatec, Triqui andAmuzgo, members of the same lineage in a progressively earlier sequence of branchingepisodes), provide fertile ground for diachronic inquiry into various lexical and grammaticaltraits of these languages, which are part of the Otomanguean phylum.The Mixtec territory can be portrayed as an intricate mosaic in its geology and vegetation. Itboasts one of the richest floras in Mexico, itself one of the most diverse areas of the planet inbiological terms. Furthermore, the Mixteca (the local name for the region in Spanish) isnotable for a high incidence of endemic species of vascular plants and terrestrial vertebrates,which reflect long series of climatic and ecological changes in the area's natural history. It ispart of a larger region of Otomanguean speech where a characteristic stone-workingtechnology has been documented by archaeologists, in conjunction with the early developmentof plant domestication and agriculture. Natural complexity and cultural history thus convergeto enhance the interest of the Mixtecan languages for ethnobotanical study.This dissertation presents the results of several years of research on the names and uses ofplants in Mixtec communities in the states of Oaxaca, Puebla and Guerrero. Extensive2information is provided on plant terminology, backed in part by herbarium specimenscollected in the field by the author. The Mixtec languages make use of a productive system ofnoun markers, in some cases matched by pronominal clitics, to label various plant categories.Adscription to these groupings appears to be determined by use, edibility and symbolicsignificance, as much as by life form affiliations that reflect adaptive design, such as woodyplants, leafy herbs, vines and grasses. Categories labeled by class terms appear consistently inall the Mixtec languages that have been documented to date. The dissertation reviews thebotanical nomenclature recorded by linguists and naturalists throughout the Mixteca since the16th century.