Periwinkle. Vincis minor.
Apocynaceae, the dogbane family.

Plant: Low, trailing plant with opposite, shiny evergreen leaves and violet, five-petaled flowers.
Flowers: Blue to violet, five petals, actually lobes of the funnel-shaped corolla, with white and violet star-like pattern in the center, 3/4"-1". The flowers are borne singly in the leaf axils.
Leaves: Opposite, ovate, shiny, evergreen and smooth-margined, to 1.5".
Blooming: April-May
Habitat: Light woods and wood margins, old gardens.

Comments: This European native, sometimes called Myrtle or Creeping Myrtle, is often grown in gardens as a groundcover. It has escaped from cultivation, and is widely distributed in North America, sometimes covering large patches of forest floor with dense colonies. The trailing plants will root at the nodes, and thus spread vegatatively to form monoclonal colonies.

Where to find it: A few patches in the woods near the parking lot. One of the early spring flowers in the park.