You can eat it boiled, like spinach, or raw in salads. They say that the forty-niners ate it to prevent scurvy. At this time of year, it grows in great stands near the paths and under trees in Almaden Quicksilver Park. I sent my son and his family up to the Park when they were here last week, so they could walk the Norton Loop that has such spectacular views of the valley.
The Latin name is: Claytonia perfoliata; there's a good article in Wikipedia. It always has this deep green look, and look completely different from other plants that grow around here. I love the way the flower seems to grow through the center of the leaf, which is actually a pair of leaves arranged to look like one. I also like the glossy look of the leaf.