Invasion

Invasion Description

1st Record: Baltimore/MD/Curtis Creek (Meredith and Schwartz 1960; Schwartz et al. 1963; USNM 203786,  United States National Museum of Natural History collections 2007)

1st Nontidal Record: Patapsco State Forest (Howard County)/MD/Patapsco River (1957, Meredith and Schwartz 1960; Schwartz et al. 1963; United States National Museum of Natural History collections 2007)

Geographic Extent

Tidal Records: Baltimore/MD/Curtis Creek (Meredith and Schwartz 1960; Schwartz et al. 1963; USNM 203786 United States National Museum of Natural History collections 2007); Joppatowne/MD/Gunpowder River (Killian et al. 2010); Edgewood/MD/Bush River (Killian et al. 2010); MD/upper tidal Patuxent River (Killian et al. 2010)

Nontidal Records: Patapsco State Forest (Howard County)/MD/Patapsco River (1957, Meredith and Schwartz 1960; Schwartz et al. 1963; United States National Museum of Natural History collections 2007); Ellicott City/MD/Patapsco River (Meredith and Schwartz 1960; Schwartz et al. 1963); Baltimore County/MD/Lake Roland (Patapsco drainage) (Meredith and Schwartz 1960; Schwartz et al. 1963); Prettyboy Dam (Harford County)/MD/Gunpowder River (Odell and Grimm 1966); Loudon County/VA/Broad Run (1977, Potomac drainage); Great Falls/VA/Potomac River (Hamilton 1979); Perryville/MD/Conowingo Reservoir, Susquehanna River (Killian et al. 2010)