It seems that I have come upon one unwelcome little plant. Garlic Mustard, Alliaria petiolata, is listed as noxious and known to take over woodlands. These photos are from a small patch up the road. Hmm... should I take 'em out?
From a Wikipedia article:
"Like most invasive plants, once it has an introduction into a new location, it persists and spreads into undisturbed plant communities. In many areas of its introduction in Eastern North America, it has become the dominant under-story species in woodland and flood plain environments, where eradication is difficult.
"The insects and fungi that feed on it in its native habitat are not present in North America, increasing its seed productivity and allowing it to out-compete native plants. It is a possible threat to the West Virginia White Butterfly (Pieris virginiensis) and Mustard White Butterfly (Pieris oleracea); adult butterflies of both species lay their eggs on native Dentaria or Toothwort plants, but they often confuse garlic mustard plants with Dentaria and lay their eggs on garlic mustard, because they have similar flowers. The eggs and young butterflies cannot live on the garlic mustard, because it has chemicals that are toxic to the larvae and eggs."