NPSpecies

Data Source: Bartgis, 1993;TNC, 1999; Wiegand, 1999; Wiegand, 2001

Data Source: Helen Hamilton

Data Source: Helen Hamilton

Park Species Detail: Wiegand, 2001: Three previously known occurrences (from Sandy Hook, Maryland to District of Columbia line) containing a total of seven individuals of Canada milkvetch (Astragalus canadensis) were successfully updated. All occur in the Potomac Gorge section of the survey area. The species is not reported from elsewhere in Maryland. A sharp decline has occurred in the known occurrences of Canada milkvetch in the gorge during recent years. Reasons for the decline are unclear, but field observations suggest deer browse may be a major negative factor. Three additional small occurrences containing approximately half of the known individuals in Maryland, and observed as late as1998, were failed updates during this survey. Bartgis, 1993: State Endangered plant, found in Potomac Fall-Line. Wiegand, 2001b: Canada milkvetch (Astragalus canadensis) is listed as extirpated from D.C. It was last reported from Chain Bridge Flats by F.V. Coville and G.R. Vasey when they collected it below Chain Bridge in 1888. It has not been reported or collected from this area since that time, 1 13 years ago. No specific survey effort to relocate this species at Chain Bridge Flats was made during 1999-2000 field surveys. However, suitable habitat remains intact in the area so there is a remote possibility that the species still occurs here.Status surveys for this species are highly recommended to fully determine its current status at Chain Bridge Flats. Wiegand, 2001b: 0 sites found. A Presumed Extirpated (SX) plant species known to occur within the District of Columbia portion of LOCO (along the C&O Canal NHP and Potomac River from the Maryland line to Key Bridge, Washington, D.C.) Also a listed species in Maryland. Wiegand, 1999: Plant species documented in the survey area (from Great Falls, Maryland, downriver to the District of Columbia) during this survey. Currently listed in Maryland as endangered or endangered/extirpated. Hamilton, 2007: See Astragalus carolinianus, a synonym., Park Species Data Source: Bartgis, 1993;TNC, 1999;Wiegand, 1999;Wiegand, 2001; Wiegand, 2001b;