This is the first report of Oplismenus hirtellus (L.) Beauv. ssp. undulatifolius (Ard.) U. Scholz for North America (Kartesz 1994 and pers. comm.). It was recently discovered by Edward Uebel in two Maryland localities. The first, in Patapsco Valley State Park, is a single population or ‘patch’ about 1.8 x 2.7 m in diameter; whereas the second location, approximately 6.4 km to the north, contains several small to large patches up to 15 m in diameter.