Flower:

Flowers are single or in leafy branching clusters at the ends of branching stems, on hairy stalks. Flowers are about ¼ inch across, the 5 petals white, widely spaced and deeply notched, appearing like 10 petals. 3 to 5 stamens (or up to 10) and a 3-parted style are in the center. The sepals are oval to egg-shaped, tapered to a point and are as long as or longer than the petals, their outer surface covered in fine hairs, usually glandular.

Leaves and stems:

The leaves are 1/3 to just over an inch long, thin, broadly oval, tapered slightly to a sharply pointed tip, rounded to wedge-shaped at the base, toothless, the upper leaves stalkless becoming progressively longer stalked lower down, hairless but with fine hairs on the stalks.

The weak stems are much branched, 4 sided with 1 row of fine hairs. Plants are mat-forming and rooting at the lower nodes, sprawling but often rising at the end of a stem (decumbent).

Notes:

An early introduction from the Old World, the common name for Stellaria media - Common Chickweed - has become as synonymous with “lawn weed” as the common dandelion. A prolific seed producer and well adapted to heavy shade, it readily rebranches and flowers below the cut of a mower blade and can be tenaciously persistent in thin areas of the lawn too shady for turf grasses. It is easily distinguished from its (also weedy) cousin Mouse-ear Chickweed (Cerastium fontana), which has similar flowers but is densely hairy.