Damasonium californicum, commonly known as fringed water-plantain or star water-plantain, is a perennial herb native to vernal pools, shallow ponds, and slow-moving streams in the western United States, particularly in California’s Central Valley, and less commonly in Washington, Oregon, Idaho, Nevada, and Montana. It typically grows 8-18 inches tall, emerging above the water surface. The plant features narrow, basal leaves with thin blades 1-3 inches long. During the late spring to early summer, it produces delicate flowers with three white or pink petals, often marked with a distinctive yellow spot at the base, which are quite showy and attract pollinators. The flowers give way to star-shaped clusters of flat, beaked achenes that are notable for their unique appearance.

Fringed water-plantain is valued for its ornamental flowers and its ability to thrive in wetland gardens or naturalized pond settings. It is often used in aquatic and riparian restoration projects due to its native status and ecological benefits, such as providing habitat for aquatic insects. In cultivation, it requires consistently moist or shallowly submerged conditions, full sun to part shade, and does best in muddy or loamy soils. While not commonly available in the nursery trade, it can be propagated by seed or division. Care should be taken to avoid introducing it into natural areas outside its native range to prevent potential invasiveness.CC BY-SA 4.0