Almost all the year round you can see low green stalks studded with small red flower buds–a splash of color usually growing intermixed with grasses. This is common sheep sorrel, or Rumex acetosella, an invasive species that was introduced from Europe. It usually grows in weedy areas, and has a long bloom period from March all the way through November.
The tart leaves are edible, and taste like redwood sorrel or lemongrass. Try it in salad or steep the leaves for a tea. The acidy-lemon flavor comes from oxalic acid–small doses are fine, but eating a lot of it can lock up calcium and other nutrients in your body.
The root can be dried, ground and made into noodles but this seems like a lot of work and I’ve never heard of anyone actually doing it. The seeds are also edible, but they are so tiny that they also aren’t practical as anything other than a novelty.
Flowers Of Marin 