Field madder (Sherardia arvensis)
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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).
Turf, pastures, orchards, vineyards, roadsides, riparian areas, oak woodlands, and grassland.
Cotyledons (seed leaves) are broadly egg shaped to nearly round, narrow at the base, often have an indented tip, and are about 1/5 to 3/5 of an inch (5–15 mm) long. The stem above the cotyledons is square in cross-section and the leaves are arranged in whorls around it. True leaves are football to egg shaped, about 1/6 to 1/3 of an inch (4–8 mm) long with short hairs and bristly tips.
Stems grow prostrate to ascending and often matlike. They are square, widely branched, and grow up to 10 inches (25 cm) long. Leaves are pointed, rough edged, 1/5 to 2/5 of an inch (5–10 mm) long, and arranged along the stem in whorls of fours, fives, or sixes. Leaves have short, straight, stiff hairs that are erect or point toward the blade tip, distinguishing it from catchweed bedstraw, Galium aparine, which has tiny curved prickles on the leaf edges and midveins that point toward the blade base.
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.
Fruits are egg shaped, about 1/12 to 1/8 of an inch (2–3 mm) long, with two lobes that separate into two nutlets at maturity.
Nutlets are oblong to egg shaped and sometimes slightly curved.
Reproduces by seed.
Related or similar plants
- Catchweed bedstraw, Galium aparine