This is one of the humble lawn weeds that are often the earliest blooms of spring, especially when they are near sources of extra heat, such as this plant next to the walk along the side of the library. Several plants are in flower and have already begun to fruit. I like to think of it as the Harbinger-of-Spring of the non-native plant world. Harbinger-of Spring or Pepper-and-Salt is often the first native plant to flower in such spring wildflower destinations as Shakerag Hollow. Although it is in the Apiaceae of Carrot Family and the bitter-cress is in the Brassicaceae or Mustard Family, their tiny white flowers close to the ground give them a somewhat similar general appearance.
This plant is also familiar to students of Professor Emeritus George Ramseur, as it was often one of the first plants they studied, as Cardamine hirsuta, in his spring semester plant systematics course (see “Sign of Spring” by Mary Priestley in the Herbarium newsletter, “The Plant Press”, Vol.X, No.1)