While such information might be of value for some purposes, we felt that our time at other herbaria was best devoted to searching for data not found in the New England Botanical Club herbarium, or in each subsequently searched herbarium, to fill in gaps in distribution. A more detailed and technical description of the mapping methodology will appear as an appendix in the final volume. Interested parties may obtain a draft of the appendix upon request to the first author. The genera are alphabetical within families, as are species within genera. Named and unnamed hybrid taxa are placed alphabetically at the end of the genus.
Unnamed hybrids combine the names of the parents alphabetically by epithet.
Species deemed to be introduced, that is, not native in New England at the time of European contact with North America, are indicated by the use of all upper case type for the scientific name. No single source of information was used in determining introduced species. For most taxa there is little dispute as to nativity. Where differences of opinion exist in the literature, we have used our own judgment based on the evidence available. A common name is supplied when it appears to be a name in general use.