Every January, the Merced Canyon opens the annual flower show with waterfall buttercups (Kumlienia hystriculus). These beauties live around wet areas where water continually drips or near waterfalls where they are kept fresh by spray. An interesting aspect of their anatomy is that they have small green petals and large white sepals, which is opposite most flowers. Green sepals and larger white (or other colored) petals are typically the norm. Look carefully at the close-up for the tiny green petals between the white structures.
How do we tell which are which? Starting at the stem of the flower the sepals always come first, then the petals, followed by the stamens (the pollen bearing parts) and finally in the center are the pistils, which receive the pollen and produce the fruit.