NPSpecies

Data Source: TNC, 1999; Wiegand, 1999; Wiegand, 2001; Wiegand, 2001b; Wiegand, 1995; ;;

Data Source: Helen Hamilton

Data Source: Helen Hamilton

Park Species Detail: Wiegand, 2001b: A previously reported occurrence for Three-leaved rosinweed (Silphium trifoliatum), listed as a highly rare plant species in D.C., was successfully updated during 1999-2000 field surveys. Four small groups totaling 50 plants were scattered across rocky flats above the river. The plants were growing in pockets of alluvial sand between rocks in prairie and savanna habitat. This is fairly level and open overwash-savanna habitat, elevated 2 to 5 meters above mean river level. The area floods frequently, probably every several years during high seasonal flows in winter and spring, and after up river storm events. Suitable habitat for three-leaved rosinweed is abundant in the vicinity, so this occurrence would be more extensive than reported here.Status surveys for this species are highly recommended to fully determine its current status at Chain Bridge Flats Survey Site. Found at 2 sites. A Highly Rare 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, 2001: Documented from Maryland during this survey from Sandy Hook, Maryland, to District of Columbia line.Watch List plant species, not officially listed by the State of Maryland nor by the Maryland Wildlife and Heritage Division. Wiegand, 1999: A Watch List species in Maryland, documented to occur in the gorge during this survey from Great Falls, Maryland, downriver to the District of Columbia line. Wiegand, 1995: Reported during this survey from Sandy Hook west to Cumberland., Park Species Data Source: TNC, 1999;Wiegand, 1999;Wiegand, 2001;Wiegand, 2001b;Wiegand, 1995;