Patuxent Research Refuge - Maryland (USFWS-PRR)

Established in 1936 by executive order of President Franklin D. Roosevelt, the Patuxent Research Refuge is the nation's only national wildlife refuge established to support wildlife research. It is located between Washington, DC and Baltimore, MD.

At the time of the Refuge's establishment in 1936, botanist Neil Hotchkiss and other scientists surveyed the flora on the 2,650 acres which made up the Refuge. Lists of plants found on the Refuge were published in 1940 and 1947. The latter list tabulated 877 plant taxa. Voucher specimens were collected and reposited in the Refuge's herbarium. By 1980, when the refuge expanded to 4,741 acres, a total of 969 plant taxa were listed.

In the early 1990's as part of the Base Re-alignment and Closure (BRAC) process, the Department of Defense transferred about 8,100 acres of land from Fort Meade to the Department of Interior, with control of the land given to the Fish and Wildlife Service. The addition of this parcel, now known as the North Tract, brought the total acreage of the Refuge to over 12,800 acres.

A floral survey of the North Tract began in 2010 and a re-survey of the older parcel of the Refuge, known as the Central and South Tracts, was initiated in 2013. As of October 2018, the herbarium holds over 5,000 voucher specimens from over 1,250 taxa found on the Refuge. This includes a number of Maryland rare, threatened, and endangered (RTE) species and at least five species new to Maryland. A number of duplicate and unique voucher specimens are held by other herbaria.

With the collaboration of the Mid-Atlantic Herbarium and the Norton-Brown Herbarium at the University of Maryland, the herbarium is digitizing its voucher specimens collection. Recently, the herbarium has added lichens to its collection.

Please feel free to peruse the herbarium's data, but use it with caution as we are still tweaking things.

For more information please contact Bill at the email address below.
Contact: Bill Harms (
Collection Type: Preserved Specimens
Management: Live Data managed directly within data portal
Global Unique Identifier: a3a739d8-2d85-4834-af69-5939f0160ad3
Live Data Download: Login for access
Digital Metadata: EML File
Patuxent Research Refuge
10901 Scarlet Tanager Loop
Laurel, MD   201708
Collection Statistics
  • 5,016 specimen records
  • 5,016 (100%) georeferenced
  • 3,928 (78%) with images
  • 4,789 (95%) identified to species
  • 149 families
  • 557 genera
  • 1,110 species
  • 1,263 total taxa (including subsp. and var.)
Extra Statistics