Carex divulsa, the sedge with many aliases
European Grey Sedge is another common name. Too bad the plant is green, not gray. It was sold as a native plant, Berkeley Sedge (C. tumulicola) for a long time, until someone checked the ID. and found that it’s not from these parts, after all. However, it does very well here, stays green as long as it has enough water, and comes back from an apparently dead state if it doesn’t. This plant reseeds.