Field madder
Sherardia arvensis

Field madder is a winter or summer annual broadleaf plant that is often weedy in turf. It is found in the San Francisco Bay region, western North Coast Ranges, Cascade Range foothills, northern Sierra Nevada foothills, western South Coast ranges, and South Coast to about 2000 feet (600 m).

Flowers bloom from January through July. Two to three small, pink to lavender, sometimes bluish, trumpet-shaped flowers cluster on the stem at the bases of leaves and have six to eight leaflike structures (bracts) underneath.