The genus Erythroxylum of theErythroxylaceae family consists of approximately 270 species of shrubs and trees, predominantly found in the tropical regions of the New World. These plants are characterized by the presence of scales (cataphylls) on their branches and by leaves that often show two lines on their undersides, forming a lighter midrib area. Their small, fragrant flowers primarily attract bees, and the fruits, about the size of a coffee bean and typically red when ripe, are mostly dispersed by birds.

Historically, the genus Erythroxylum> has been the subject of botanical, chemical, and anthropological studies due to its cultural and economic significance, particularly for containing alkaloids such as cocaine in several of its cultivated species. The pioneering research of Timothy Plowman during the 1970s and 1980s laid the foundation for understanding the taxonomy, ecology, and ethnobotany of coca plants. In his taxonomic studies, Plowman clarified the identity of the cultivated plants, recognizing four ancestral varieties in South America: Erythroxylum coca var. coca (Huánuco or Bolivian Coca), E. coca var. ipadu (Amazonian Coca), E. novogranatense var. truxillense (Trujillo Coca), and E. novogranatense var. novogranatense (Colombian Coca). Alongside this taxonomic delineation, his studies included a hypothesis regarding the spatial-temporal origins of these cultivated varieties. According to Plowman, domestication may have originated in the central Andes with E. coca var. coca, from which E. coca var. ipadu derives, while a separate lineage gave rise to E. novogranatense var. truxillense, which in turn led to E. novogranatense var. novogranatense.

However, more recent studies, such as that of Dawson White and collaborators (2021), have refined and challenged these ideas, revealing a greater complexity in the domestication and diversification of coca varieties. Genomic analyses have supported a new hypothesis suggesting multiple independent origins from the domestication of a wild ancestor, Erythroxylum gracilipes. This discovery expands on Plowman’s theories, providing a more nuanced understanding of the evolution and spread of cultivated coca varieties in South America.