Smithsonian National Museum of Natural History

Website Search Box

Department ofBotany


 Map of the Flora of the Flora of the Washington-Baltimore Area

 Historic DC Map of 1917

 DC Gazetteer of collections localities

Query the DC Flora Checklist

The aim of this project has been to revise completely Frederick J. Hermann’s much outdated and long out-of-print A Checklist of Plants in the Washington-Baltimore Area (ed. 2), published in 1946 in duplicated form. The publication of the Annotated Checklist of the Vascular Plants of the Washington-Baltimore Area, the new revision by Stanwyn G. Shetler and Sylvia S. Orli, includes two parts, Part I, Ferns, Fern Allies, Gymnosperms, and Dicotyledons (186 p.) and Part II, Monocotyledons (95 p.). It is hoped that the revised checklist will become the basis for preparing a completely new manual of the flora of the Washington-Baltimore Area, to replace the 1919 Flora of the District of Columbia and Vicinity of A. S. Hitchcock and P. C. Standley (see Bibliography under Main References).

Species Coverage - The Checklist includes all native and naturalized species of vascular plants (ferns and fern allies, conifers [gymnosperms], flowering plants [angiosperms]) known to occur in the geographic area as defined. Naturalized species are plants that have been introduced to the area in some manner and are now known or believed to be reproducing naturally in the wild, even if only sporadically. The new Checklist includes a total of 2794 species - 1801 native species and 993 introduced species. Thus, naturalized alien species make up nearly 37% of the total flora. Of the total, 2001 species (1220 native, 781 introduced [39%]) are in Part I, and 793 species (581 native, 212 introduced [27%]) are in Part II. Categories below the rank of species are not being recognized formally in the Checklist, but may be mentioned in comments or cited as synonyms under the relevant species.

You can download the pdf version of Part I and Part II (you must have Adobe Acrobat Reader to read this document).

Geographic Coverage - The "Washington-Baltimore Area," as defined by the Conference on District Flora and published in the introduction to Hermann's Checklist (1941, 1946), is bounded on the north by the Maryland-Pennsylvania line, on the east by the Chesapeake Bay, on the south by the Rappahannock and Rapidan rivers, and on the west by the east foot of the Blue Ridge Mountains (see Map). Thus, the Bull Run and Catoctin mountains are included, but Shenandoah National Park and the Eastern Shore are excluded.

This area encompasses the District of Columbia and the following cities and counties of Maryland and Virginia, lying within roughly a 50-mile radius of Washington:


Counties: Anne Arundel, Baltimore, Calvert, Carroll, Charles, Frederick, Harford, Howard, Montgomery, Prince George's, St. Mary's. Cities: Baltimore


Counties: Arlington, Culpeper, Fairfax, Fauquier, King George, Lancaster, Loudoun, Northumberland, Prince William, Richmond, Stafford, Westmoreland. Cities: Alexandria, Fairfax, Falls Church, Manassas

The Washington-Baltimore Area, as defined, represents a radius of coverage from the Capitol in Washington, DC., of about 50 miles, greatly expanded beyond the 15-mile radius of the earlier Floras of L. F. Ward (1881) and Hitchcock and Standley (1919). This also was the radius of coverage for the initial District of Columbia Herbarium, specimens originally pulled out from the general collections of the U. S. National Herbarium in the Department of Botany of the National Museum of Natural History, Smithsonian Institution. Nearly all the species formally recognized in the Hitchcock and Standley Flora were based on specimens in the District of Columbia Herbarium, which came to be known as the D. C. Herbarium. This herbarium was expanded in the 1940s (by transferring additional specimens from the general herbarium) to cover the larger Washington-Baltimore Area, in order to support the then newly defined flora project. The D.C. Herbarium has been maintained on this expanded geographic scale ever since and has served as the primary basis of the current Checklist project.

Revision Procedures - The starting point for Shetler and Orli's Annotated Checklist was a combined list of all the species recognized in Hitchcock and Standley (1919) and Hermann (1946). This preliminary list was checked species by species against the D.C. Herbarium and the current principal reference sources for Maryland and Virginia (see Main References). Species were accepted into the formal Checklist draft on the basis of either one or more voucher specimens in the Herbarium or a reliable published record, as in Brown and Brown (1972, 1984) or Harvill et al. (1992). The preliminary list was also checked against the current principal manuals and other floristic references for the region, to rationalize taxonomic and nomenclatural usage. Every effort was made to account for all the species that had been recognized and the names that had been widely used in the region since the publication of the Flora of Hitchcock and Standley, as well as for species newly reported for the Area in the recent botanical literature.

[ TOP ]