Wild buckwheat (Polygonum convolvulus)
Click on images to enlarge
Wild buckwheat, also known as black bindweed, is an annual broadleaf with arrowhead-shaped leaves. It inhabits disturbed places such as agricultural land (especially grain fields) and landscaped areas. Wild buckwheat is found throughout California, except deserts, up to an elevation of about 7000 feet (2100 m).
Agronomic and vegetable crop fields—especially grain fields, livestock farms and dairies, landscaped areas, gardens, roadsides, and other disturbed places.
Cotyledons (seed leaves) are long and broad, with rounded tips and a granular white powdery surface. The first true leaves are arrowhead shaped, with a rough stalk that forms a tight sheath around the base of the stem.
Mature plants have trailing stems up to 8 to 40 inches (20–100 cm) long, and are often mistaken for field bindweed, except that its leaves are more pointed.
Flowers bloom from May through September. Clusters of inconspicuous, green flowers form at bases of leaves, or at stem tips.
Fruits are tiny, single seeded, have three sides and are often concave, dull to slightly glossy, and dark brown to black.
Wild buckwheat reproduces by seed.