Debates over Cannabis sativa L. and C. indica Lam. center on their taxonomic circumscription and rank. This perennial puzzle has been compounded by the viral spread of a vernacular nomenclature, "Sativa" and "Indica," which does not correlate with C. sativa and C. indica. Ambiguities also envelop the epithets of wildtype Cannabis: the spontanea versus ruderalis debate (i.e., vernacular "Ruderalis"), as well as another pair of Cannabis epithets, afghanica and kafirstanica. To trace the rise of vernacular nomenclature, we begin with the protologues (original descriptions, synonymies, type specimens) of C. sativa and C. indica. Biogeographical evidence (obtained from the literature and herbarium specimens) suggests 18th-19th century botanists were biased in their assignment of these taxa to field specimens. This skewed the perception of Cannabis biodiversity and distribution. The development of vernacular "Sativa," "Indica," and "Ruderalis" was abetted by twentieth century botanists, who ignored original protologues and harbored their own cultural biases. Predominant taxonomic models by Vavilov, Small, Schultes, de Meijer, and Hillig are compared and critiqued. Small's model adheres closest to protologue data (with C. indica treated as a subspecies). "Sativa" and "Indica" are subpopulations of C. sativa subsp. indica; "Ruderalis" represents a protean assortment of plants, including C. sativa subsp. sativa and recent hybrids. Keywords Cannabis sativa * Cannabis indica * Taxonomy * Nomenclature