Polygonum fowleri subsp. fowleri

Family: Polygonaceae · Type: annual · Native

Fowler's knotweed is a California native annual found in northern coastal and San Francisco Bay bioregions on sandy, gravelly seashores at elevations below 10 meters. Flowering from July to October, this plant produces white to pink flowers in small clusters along its prostrate to ascending stems. Growing up to 50 centimeters long with succulent green, ribbed stems that branch from the base, it develops distinctive elliptic to elliptic-obovate leaves 20 to 35 millimeters long. Its leaves have flat margins and obtuse tips, with small ocreae (stipule-like sheaths) 4 to 12 millimeters long that disintegrate into fibers. The fruit is widely ovate, 3 to 3.7 millimeters long, with a shiny brown to dark-brown surface and a distinctive beak-like tip.

Habitat: Sandy, gravelly seashores

Bloom period: Jul-Oct

Elevation: < 10 m

Bioregions: NCo, SnFrB

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Jepson eFlora, Cal-IPC, and more.