"Nuu Savi" ("Sacred Rain's collectivity"), the Mixtec people of southern Mexico, had created some of the most complex polities in the continent at the time of European contact. Five hundred years later, they remain cohesive, culturally distinct communities, as increasing numbers of individuals and families migrate to northern Mexico and the US for work in the agricultural and service sectors. In 2005, the Mexican Federal Government reported there were more than 446,000 speakers of "Tu'un Savi" ("Sacred Rain's word," the Mixtec languages) five years of age and older, 322,000 of them still living in 1551 settlements within their historic homeland; an additional 100,000 to 200,000 are estimated to reside in the US. The term Mixtec, derived from the Nahuatl "mixte:cah" ("cloud-people"), has been considered by different authors to encompass between 12 and 52 mutually unintelligible languages, in addition 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. The "Instituto Nacional de Lenguas Indigenas," however, recognizes 81 variants of Mixtec, making it the most diversified language group in Mexico following official criteria. The internal variation of Mixtec and its geographic proximity to three related groups (Cuicatec, Triqui and Amuzgo, members of the same lineage in a progressively earlier sequence of branching episodes), provide fertile ground for diachronic inquiry into various lexical and grammatical traits 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. It boasts one of the richest floras in Mexico, itself one of the most diverse areas of the planet in biological terms. Furthermore, the Mixteca (the local name for the region in Spanish) is notable 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 is part of a larger region of Otomanguean speech where a characteristic stone-working technology has been documented by archaeologists, in conjunction with the early development of plant domestication and agriculture. Natural complexity and cultural history thus converge to 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 of plants in Mixtec communities in the states of Oaxaca, Puebla and Guerrero. Extensive information is provided on plant terminology, backed in part by herbarium specimens collected in the field by the author. The Mixtec languages make use of a productive system of noun 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 symbolic significance, as much as by life form affiliations that reflect adaptive design, such as woody plants, leafy herbs, vines and grasses. Categories labeled by class terms appear consistently in all the Mixtec languages that have been documented to date. The dissertation reviews the botanical nomenclature recorded by linguists and naturalists throughout the Mixteca since the 16th century. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]