Scope of the Work

Flora of North America North of Mexico is a synoptic floristic account of the plants of North America north of Mexico: the continental United States of America (including the Florida Keys and Aleutian Islands), Canada, Greenland (Kalâtdlit-Nunât), and St. Pierre and Miquelon. The flora is intended to serve both as a means of identifying plants within the region and as a systematic conspectus of the North American flora. Taxa and geographical areas in need of further study also are identified in the flora. Taxa thought to have become extinct during the period of permanent European settlement, i.e., the past 500 years, are included in the flora. Flora of North America North of Mexico will be published in 30 volumes. Volume 1 contains background information that is useful for understanding patterns in the flora. Volume 2 contains treatments of ferns and gymnosperms. Families in volumes 3 – 26, the angiosperms, are arranged according to the classification system of A. Cronquist (1981). Bryophytes will be covered in volumes 27 – 29. Volume 30 will contain the cumulative bibliography and index.

How To Cite this Work

The currently correct basic citation for Flora of North America as a whole is:

Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 19+ vols. New York and Oxford.

The currently correct expanded citation for Flora of North America as a whole is:

Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 15+ vols. New York and Oxford. Vol. 1, 1993; vol. 2, 1993; vol. 3, 1997; vol. 4, 2003; vol. 5, 2005; vol. 7, 2010; vol. 8, 2009; vol. 19, 2006; vol. 20, 2006; vol. 21, 2006; vol. 22, 2000; vol. 23, 2002; vol. 24, 2007; vol. 25, 2003; vol. 26, 2002; vol. 27, 2007; vol 28, 2014; vol 9, 2014; vol 6, 2015.

To cite a particular part of one of the published volumes, use the following model:

Boufford, D. E. 1997. Fumaria. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 19+ vols. New York and Oxford. Vol. 3, pp. 356-357.

To cite a particular part of a volume not yet published, use the following model:

Freeman, C.C. and F. Zapata. In prep. Escalloniaceae. For: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 19+ vols. New York and Oxford. Vol. 13.


The published flora includes accepted names, literature citations, selected synonyms, identification keys, summaries of habitats and geographic ranges, descriptions, chromosome numbers, phenological information, and other biological observations. Economic uses, weed status, and conservation status are provided from specified sources. Each volume contains a bibliography and an index to the taxa included in the volume. A comprehensive, consolidated bibliography and comprehensive index will be published in the last volume. The treatments, written and reviewed by experts from throughout the systematic botanical community, are based on original observations of herbarium specimens and, whenever possible, on living plants. These observations are supplemented by critical reviews of the literature.

Basic Concepts

Our goal has been and continues to be to make the flora as clear, concise, and informative as practicable so that it can be an important resource for both botanists and nonbotanists. To this end, we are attempting to be consistent in style and content from the first volume to the last. Readers may assume that a term has the same meaning each time it appears and that, within groups, descriptions may be compared directly with one another. Any departures from consistent usage will be explicitly noted in the treatments (see also References below).

Treatments are intended to reflect current knowledge of taxa throughout their ranges worldwide, and classifications are therefore based on all available evidence. Where notable differences of opinion about the classification of a group occur, appropriate references are mentioned in the discussion of the group.

Documentation and arguments supporting significantly revised classifications are published separately in botanical journals before publication of the pertinent volume of the flora. Similarly, all new names, names for new taxa, and new combinations are published prior to their use in the flora. No nomenclatural innovations will be published intentionally in the flora. Journals and series in which papers relevant to Flora of North America North of Mexico have been or may be published include Brittonia, Canadian Journal of Botany, North American Flora, Novon, Systematic Botany, Systematic Botany Monographs, and Taxon, among others.

Taxa treated in full include native species, native species thought to be recently extinct, hybrids that are well established (or frequent), and waifs or cultivated plants that are found frequently outside cultivation and give the appearance of being naturalized. Taxa mentioned only in discussions include waifs or naturalized plants now known only from isolated old records and some nonnative, economically important, or extensively cultivated plants, particularly when they are relatives of native species. Excluded names and taxa are listed at the ends of appropriate sections, e.g., species at the end of genus and genera at the end of family.

Treatments are intended to be succinct and diagnostic but adequately descriptive. Characters and character states used in the keys are repeated in the descriptions. Descriptions of related taxa at the same rank are directly comparable. With few exceptions, taxa are presented in taxonomic sequence. If an author is unable to produce a classification, the taxa are arranged alphabetically, and the reasons are given in the discussion. Treatments of hybrids follow that of one of the putative parents. Hybrid complexes are treated at the ends of their genera, after the descriptions of species.

We have attempted to keep terminology as simple as accuracy permits. Common English equivalents have been used in place of Latin or Latinized terms or other specialized terminology whenever the correct meaning could be conveyed in approximately the same space, e.g., "pitted" rather than "foveate," but "striate" rather than "with fine longitudinal lines." Specialized terms that are used are defined in the generic or family descriptions and, in some cases, are illustrated.


Authoritative general reference works used for style are The Chicago Manual of Style for Authors, Editors, and Copywriters, ed. 13 (University of Chicago Press 1982); Webster's New Geographical Dictionary (Merriam-Webster 1988); and The Random House Dictionary of the English Language, ed. 2, unabridged (S. B. Flexner and L. C. Hauck 1987). B-P-H/S. Botanico-Periodicum-Huntianum/Supplementum (G. D. R. Bridson and E. R. Smith 1991) has been used for abbreviations of titles of serials; and Taxonomic Literature, ed. 2 (F. A. Stafleu and R. S. Cowan 1976--1988) and its supplements by F. A. Stafleu, E. A. Mennega, and others (1992+) have been used for abbreviations of titles of books.