Common chickweed

James Altland, USDA-ARS
Branching, leafy stems of common chickweed run prostrate along the ground, commonly forming small mounds 4-12 inches high.
James Altland, USDA-ARS
James Altland, USDA-ARS
Foliage is oppositely arranged along the stem.
James Altland, USDA-ARS
James Altland, USDA-ARS
Common chickweed flowers have 5 petals. The petals are deeply lobed, so much so that it appears that there are 10 petals.
James Altland, USDA-ARS
James Altland, USDA-ARS
Common chickweed stems also root at internodes. Rooting at the internodes, along with the inherent brittle stems of chickweed,
James Altland, USDA-ARS
Stellaria media
Life cycle: 
Common chickweed is mostly prostrate, and often grows erect by growing on top of itself, forming small mounds or mats. Foliage is opposite, simple, and ovate to elliptical. Foliage is generally glabrous (without hairs), although the petioles are hairy, and sometimes the base of the leaf is as well.
White ½” flowers are produced in clusters at the terminal end of the stem. Each flower has 5 petals, each so deeply bi-lobed that it appears to have 10 petals. Flowering occurs in the spring.
Favorable environments: 
Favorable environment notes: 
Common chickweed can grow in a variety of locations. It prefers fertile, moist disturbed sites such as ornamental plantings, lawn areas, gardens and field nurseries. It also thrives in many agricultural crops, vineyards and orchards.
Common chickweed reproduces by seed or by stems rooting at inter-nodes. One plant can produce many generations of seedlings during a season.
Of interest: 
Common chickweed is sometimes confused with mouseear chickweed-Cerastium vulgatum and scarlet pimpernel-Anagallis arvensis. It is edible and is used in salads and as a food for caged domestic birds.