California Buttercup, Ranunculus californicus, is a perennial herb with glossy, deep yellow flowers featuring 9-17 petals.  Native to much of California, Baja California, Oregon, and Pacific coastal islands, it blooms in late winter to spring, as a low ground cover.  The large green swelling in the center of the flower consists of the carpels, which produce ovules.  There are numerous stamens with large anthers which produce the pollen.  In young flowers, the stamens wrap around the carpels.  

​Unlike most flowers that have a pool of nectar in a single nectary, the buttercup dispenses her sweet treats discreetly in little pockets at the base of each petal, ensuring that the visiting pollinator would probe meticulously and thoroughly around the flower, and get covered with her sticky pollen.