Stellaria holostea L.
Family: Caryophyllaceae
adder's-meat,  more...
[Alsine holostea (L.) Britton]
Stellaria holostea image
from USDA Plants website  
Etymology: Stellaria: from the Latin stella for "star" because of the star-like shape of the flowers or some other feature
Plants: perennial forb
Conservation Status: Introduced - adventive