Congdon's Tarplant

Threatened and Endangered Species

Congdon's tarplant (Centromadia [Hemizonia] parryi subsp. congdonii) is a rare member of the sunflower family. This small, spiny annual was once more common in the San Francisco Bay Area, but much of its habitat has been eliminated by development. Because it tends to prefer moist clay soils, it usually grows and flowers during the late-spring and early summer, when other annual plants are dry and have gone to seed. The California Native Plant Society considers the plant rare and endangered (its List 1B), but it has no state or federal status. Congdon's tarplant is found in grasslands and seasonal wetlands from the Bay Area to San Luis Obispo County. It occurs on the WHF Intervening Properties and Wendt Ranch preserves.