Selfheal or Heal All,  Prunella vulgaris
Lamiaceae or Mint Family

Plant Low plant, usually under a foot tall.  Stem square in cross-section.  Leaves opposite each other, egg-shaped to lance-shaped, sometimes with a few teeth.  Lower leaves long stalked.  Usually two very narrow leaves (actually bracts) underneath the flowerhead.  Flowers purple, irregular, with large upper and lower lips and two small side petals, in dense spikes.  Leaves, bracts and sepals of flowers often tinged purplish.

Although native, a very common weed of lawns, fields, gardens, roadsides and waste places.  In Wildwood. common along the bike way and Wildwood Drive. 

At first glance, could be confused with gill-over-the-ground and purple dead-nettle, but these species are lower, bloom earlier, and have heart-shaped, scalloped leaves.