Atlas of the Flora of New England

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The origins of this project were the creation in the early 1980s of paper charts of the New England counties for the vascular plant species of New England by one of us (Angelo). The charts were used as a sieve or filter for determining which of the large backlog of unmounted specimens filled county gaps in the collection of the New England Botanical Club at Harvard University. Since the herbarium of the New England Botanical Club is easily the largest collection of New England vascular specimens, David Boufford suggested using the charts as a basis for mapping the distributions of the New England vascular flora by including records from the Harvard University Herbaria and other herbaria in New England. With the beginning of publication of the Flora of North America we decided to publish our New England distributions in installments using the taxonomy of that project and initially aligning our installment with the volumes of that project. Our first installment was published in 1996, and the last installment was published in 2014, as detailed in the Bibliography. With the development of an application by Ray Angelo for displaying a map of county distributions on a web site on-the-fly from a database of records we began in 2001 to make our installments with updated maps available on these pages. Following the publication of our last installment in 2014 in Phytoneuron, which completed the coverage of all New England taxa, the entire web site was reorganized, revised, updated and corrected as of December 2016.

The number of taxa included in the Atlas are as follows:

4,112 -- total
2,471 -- native taxa (60.09 %)
1,641 -- alien taxa (including hybrids with at least one alien parent) (39.91 %)
  517 -- hybrids (12.57 %)
1,066 -- genera
  595 -- genera with native taxa
  183 -- families

The New England background maps for the application are adapted from a more detailed custom map provided generously by Ray Sterner whose map web site is at: The maps are in color and show topography. Lowest elevations are green and higher elevations become progressively more brown with the highest elevations purplish and white. The distributions reflect the most current state of our distribution data. Not all taxa are mapped. Some obscure, native taxa (mostly Crataegus) are known only from their type location or the type location and just one or two other locations. Other taxa have not been segregated from a closely related taxon in New England herbaria. In those cases a note in the text indicates that the combined taxa are mapped under the name most frequently encountered on the specimens. A spreadsheet at contains all distribution data. Each record of occurrence is given a letter code for a herbarium where a voucher is located. The explanation of the letter codes is contained in an additional sheet in the spreadsheet tabbed at the bottom. An additional spreadsheet at the same location lists 336 taxa that have been reported in other references to occur in New England. The Excluded Taxa page gives more information about these excluded taxa.

This web site presents the distributions of the vascular flora of New England in the form of dot distribution maps at the county level. New England comprises the six northeastern states of the United States: Maine, New Hampshire, Vermont, Massachusetts, Rhode Island and Connecticut. These states range in latitude from 41°N to 47°28'N and in longitude from 67°W to 73°45'W. The elevation of the region extends from sea level to 1,898 m (6,228 ft) at the summit of Mt. Washington, New Hampshire, the highest mountain in northeastern United States and the most prominent mountain in the United States east of the Mississippi River. The total area of the region is 172,515 km2 (66,608 miles2) including bodies of water; the total land area is 163,157 km2 (62,995 miles2). The effects of continental glaciers, which covered the entire region several times during the Pleistocene, and the last of which did not retreat until about 15,000 years ago, are still clearly evident throughout the area. The state by state statistics on size and elevation are shown in Table 1 (Merriam-Webster, Inc. 1984).

Total Area
Land Area
Elevational Range
86,028 km2
80,117 km2
0-1,606 m
New Hampshire
24,097 km2
23,395 km2
0-1,898 m
24,887 km2
24,020 km2
29-1,339 m
21,386 km2
20,287 km2
0-1,064 m
Rhode Island
3,144 km2
2,725 km2
0-248 m
12,973 km2
12,613 km2
0-725 m

Table 1. Total area, land area, and range in elevation for the six New England states.

The more southerly states of Massachusetts, Rhode Island, and Connecticut are densely populated (the least densely populated of these three states, Connecticut, had an average of 286 persons per km2 in 2011; Janssen 2013). The northern states of Maine, New Hampshire, and Vermont are mostly rural (the most densely populated of these three states, New Hampshire, had an average of 57 persons per km2 in 2011; Janssen 2013).

This work encompasses all vascular plants (pteridophytes and spermatophytes) at the rank of species, subspecies, and variety growing as established, reproducing populations in wild habitats in the New England states. Our data are based solely on herbarium specimens in non-private collections of universities, botanical gardens, arboreta and other publicly accessible collections of nonprofit organizations. We have excluded specimens from our records that are spontaneous in gardens, in lawns, in yards, on the grounds of arboreta, nurseries, school campuses, in seeded fields, persistent at old house sites or other plantings, etc. We have also excluded waifs and records for alien plants where the habitat or degree of spreading for woody plants is not specified on the specimen. Also, specimens of alien species where no habitat is provided have been omitted. Other checklists and floras commonly include such records. A list of Excluded Taxa is provided to detail a large number of taxa reported from our region by other works. Hybrids have been included, but forms and other ranks below the level of variety are not. Our distribution data are based on voucher specimens primarily in the herbaria of New England.

It is our hope that this work will stimulate additional field work to supplement the distributions portrayed in the maps. The herbarium of the New England Botanical Club has proven to be the most important resource for this project and is especially eager to receive specimens documenting range extensions. We also would like to be informed of such specimens in other herbaria. Similarly, we welcome notification of publication of new taxonomic studies that include New England taxa or new, documented chromosome counts for taxa in the New England flora.


Most of our records are from specimens in the New England Botanical Club herbarium (NEBC) and New England specimens of the Harvard University Herbaria (GH, A, AMES, ECON). This has been supplemented by records from other herbaria in the region that we visited and/or that have web sites with images of specimens, such as the University of Connecticut (CONN), the University of Massachusetts at Amherst (MASS), the University of Vermont (VT). For the herbarium of the University of Maine (MAINE) in Orono we relied on the notebooks of Harry E. Ahles at MASS combined with the online database for MAINE and communication with individuals in Orono who checked information on specimens for us. More recently the Consortium of Northeastern Herbaria (CNH) and online imaged specimens at Yale University (YU) and have provided us with access to additional specimens at other herbaria that we did not visit. We obtained some records for native taxa from systematic treatments where the information on voucher specimens cited was sufficiently specific to provide county data and the name of the herbarium where the specimens were deposited. To complete this project in a reasonable period of time our records are merely the presence or absence at any time in the past within a given New England county and the herbarium of the voucher specimen. Multiple records for a given county were not recorded. Priority was given first to specimens from NEBC, then to specimens in the Harvard University Herbaria, then to specimens of the state university herbaria (MAINE, NHA, VT, MASS and CONN). Our current records are contained in Spreadsheets.

The data represented currently by specimens in New England herbaria best depict vascular plant distributions when displayed at the county level. Attempting to display such data by the exact geographical coordinates of each collection locality, or even at the township level, distorts the actual distributions. By such detailed mapping, patterns tend to reflect concentrated collecting along major highways and clustering near university cities and towns, popular resort areas, and botanical hot spots. This was evident from some of the detailed distribution maps produced about 35 years ago by the plant distribution committee (now defunct) of the New England Botanical Club. The distortions portrayed by such detailed mapping are resolved (smoothed out) by plotting data only at the county level.

The counties of New England range in size from Bristol County, Rhode Island (65 km2, or 25 mi.2), to Aroostook County, Maine (17,666 km2, or 6,821 mi.2 - land only). The great majority of counties, however, are between 1,300 km2 (500 mi.2) and 3900 km2 (1,500 mi.2). To reduce the size disparity at the large end, and to depict distributions more evenly, the largest Maine counties are subdivided. Penobscot, Piscataquis, Somerset, and Oxford counties have been divided arbitrarily into roughly equal-sized, north and south sectors along township boundaries. Aroostook County, the largest county, is divided into three sectors. Coös County, New Hampshire, is divided into north and south sectors. The division of Coös County isolates the White Mountains, which harbor an alpine flora associated mostly with New England's highest peak, Mount Washington. Figure 1 shows the location of states and counties of New England and the subdivisions of the largest counties.

In recording the collection data no attempt was made to verify the accuracy of the identification of every specimen, but obvious misidentifications were annotated with corrections. Even though the basis for a particular county record might be a misidentified specimen, for plants common within New England, our view is that the taxon most likely occurs within the county. Specimens documenting disjunct or marginal occurrences of native taxa (or otherwise rare, endangered or threatened taxa) usually have received greater scrutiny in herbaria, because of a heightened interest in rare plants nationwide, and are less likely to be misidentified.


The taxonomy and nomenclature adopted for this work essentially follow the Flora of North America (Flora of North America Editorial Committee 1993 -). The primary exceptions are that for plant families and genera we follow the Angiosperm Phylogeny Website, for pteridophytes we follow the families and genera of Smith et al. (2006), and for Poaceae taxonomy we followed with few exceptions the Catalog of New World Grasses. In some cases we followed the taxonomy in studies published after the corresponding treatment appeared in the Flora of North America. We have limited this to studies that gained wide acceptance, or that we believed would gain wide acceptance. The authorship of the scientific names in this atlas has been reviewed using multiple sources, and in cases of discrepancies or ambiguities nomenclatural specialist Dr. K.N. Gandhi consulted, such that we believe our work is more accurate than any other single reference.

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, but the opinion of the esteemed New England botanist, Merritt L. Fernald, has been given great weight. 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 and not merely a translation of the scientific name. Common names used in New England have been given preference.

Cited chromosome numbers are taken primarily from the Chromosome Counts Database and Tropicos. Very few of the counts are based on material from New England, but instead reflect counts made from throughout the range of the taxon. When a particular chromosome number has been reported significantly less frequently than others for a given taxon, it is enclosed within parentheses.

The habitat data are distillations from a variety of sources augmented by our own field observations. An attempt was made to indicate habitat information as it applies to a particular taxon in New England rather than to the entire range of the taxon. In cases where a given taxon is represented in New England with one or just a few voucher specimen, the habitat given is limited to that given on the specimen rather than the range of habitats over its geographical distribution as given in manuals.

Synonymy is provided primarily with respect to names in the standard manuals used for New England, Fernald (1950), Gleason and Cronquist (1991), and Seymour (1982), since the majority of specimens in New England herbaria were identified using the names in these manuals or were later annotated using the names in those manuals.

ACKNOWLEDGMENTS. The acknowledgments include all who helped us over the past 20 years of this project. We thank the curators and directors of the herbaria of Brown University, Harvard University, the University of Connecticut, the University of Maine, University of Massachusetts, the University of New Hampshire, the University of Rhode Island, and the University of Vermont for allowing us access to their collections. We particularly appreciate the kindness of David Barrington, Chris Campbell and Karen Searcy for allowing use of the collections in their care outside of normal hours of operation. We are grateful also to Karen Searcy and Roberta Lombardi for facilitating access to the notebooks of Harry E. Ahles at the University of Massachusetts, for bringing to our attention some new voucher specimens there and for checking voucher information. Leslie J. Mehrhoff was very generous in sharing data on specimens that he collected that are in the herbaria at the University of Connecticut and Yale University, and in reviewing our Connecticut data, providing many additional records. James Hinds assisted by checking extensively voucher specimens at the University of Maine herbarium. David Barrington, David S. Conant, and James Hickey made many helpful comments on our pteridophyte manuscript, and Warren H. "Herb" Wagner. Jr. was particularly helpful and encouraging. We thank Bruce A. Sorrie for collecting data from the Harvard University herbaria in the early stages of this project. We also appreciate the check for voucher specimens by Robert Capers, Janet Sullivan, John Kartesz, Steve Rawson, Cathy Paris, Tom Vining, Chris Campbell, James Solomon, Donald Les, Jennifer Doubt, Walter Kittredge, Anthony Brach, Emily Wood, Lisa I. Palmer, Craig Layne, Elizabeth Allen, Gisèle Mitrow, Jennifer Doubt, Alina Freire-Fierro, James Morefield, Lauren Sopher, Patrick Sweeney, Ian Medeiros, Misha Cetner, Karoline Oldham, John C. McPeek, Tim Whitfield, Nicole Tarnowsky, Bethany Brown, Ken Yamazaki and Christine Niezgoda. Michael Sundue facilitated the checking of specimens at his institution. Mary Barkworth graciously reviewed our Poaceae and very generously provided updates for the nomenclature and taxonomy of several groups to bring them into agreement with a forthcoming Manual of Grasses for the Continental United States and Canada. Barre Hellquist gave especially generously of his time and knowledge to provided much information on the aquatic groups. Anthony Reznicek provided many valuable corrections, additional records and comments, checked voucher specimens, and reviewed some specimens whose identifications were in question. Gordon Tucker provided information on many vouchered records, primarily at Eastern Illinois University (EIU) and his expertise in Cyperaceae. George Argus and Robert Bertin kindly provided information about Salix vouchers. Ihsan A. Al-Shehbaz generously provided much assistance with questions relating to Brassicaceae and checked for vouchers in other families. Janet Sullivan kindly shared portions of her Flora of North America draft treatment of Physalis and checked voucher specimens in other groups. Art Gilman provided information about Leucophysalis. The following botanists were consulted in their areas of expertise: Guy Nesom, Alan Weakley, Charles Sheviak, Magnus Lidén, Dwayne Estes, John Nelson, Warren Wagner, Karol Marhold, Craig Greene, Richard Abbott, and Carlos Aedo. Heidi Schmidt and James Zarucchi provided us with information regarding Flora of North America treatments. Erika Sonder assisted with reviewing specimens at the Harvard University Herbaria. Andrew Mckenna-Foster of the Maria Mitchell Association kindly provided the latest database file of that organization’s herbarium records. We thank Arthur Haines for review comments on two of our installment publications of this project, for research into voucher specimens, and for providing many updates after the print publication of this atlas. John Kartesz and Misako Nishino generously provided the latest draft of the Floristic Synthesis of North America, which was consulted for reports of occurrence and sources of such reports. Kancheepuram Gandhi provided valuable assistance in settling nomenclatural issues. If we have overlooked anyone, we offer our sincere thanks and apologies. Please notify us of the omission so that we can formally acknowledge your assistance.

Designed by Ray Angelo. Revised Feb. 21, 2017