Harvey E. Ballard Jr, John T. Kartesz, Misako Nishino
The Journal of the Torrey Botanical Society 150 (1), 3-266, (29 March 2023) https://doi.org/10.3159/TORREY-D-22-00029.1
KEYWORDS: northeastern North America, taxonomic treatment, Violaceae, violets
A taxonomic treatment is presented for the violets (Violaceae) confirmed in the range described in the second edition of Gleason and Cronquist's Manual of Vascular Plants of Northeastern United States and Adjacent Canada, in advance of the new treatment of this manual that is in preparation. Recent field, herbarium, and laboratory investigations of eastern North America's violet flora by the author and students have reexamined eastern North American violet taxa and utilized multiple sources of evidence filtered through modern species concepts to delimit taxa and assign appropriate taxonomic rank. Results have led to the recognition of 58 native and eight introduced species, one subspecies, one variety and one form, 10 informal variants, and 113 wild hybrids in our region, representing the genera Cubelium, Pombalia, and Viola. In Viola, two new species are described and three new combinations are made (one to species rank, one to subspecies, and one to forma), and eight names are typified. Viola taxa are distributed across five sections and nine subsections and are representative of most of the infrageneric taxonomic diversity in North America overall. Anomalous variants in Viola emarginata, Viola palmata, Viola septentrionalis, and Viola sororia currently lack sufficient information for taxonomic decisions but are presented to encourage study, collection, and documentation. Six potential taxa occur adjacent to or very near our region and may eventually be discovered in our area; they are included in the keys and briefly described with figures. The treatment includes introductory text, dichotomous keys, synonymy with some type information, detailed descriptions, and other information, as well as color figures of habit and plant structures and US county-level geographic distribution maps for nearly all included taxa.