Tough to tell from a distance, but I'm going to guess Carex comans 'Green.' New Zealand Hair Sedge.

It is a sedge but a native one, Carex tumulicola, commonly known as Berkeley sedge or foothills sedge. It is frequently planted as a groundcover in California and sometimes as a lawn substitute and is characterized by its rolling, sea-like quality. And it is very drought tolerant, adding to its popularity.

It's a dynamite look, massed like that. I especially like the 4th photo. Greenlee says it grows well from seed.

Greenlee also says zone 8, but Darke says zone 7. I'll have to see if I can find some seed.

Thank you All! The photos are N CA East Bay Hills near Cal State. I think it is zone 9 but I have never figured out how to apply zones in our micro climates, so I just experiment to see what thrives. I did collect a few seeds last year and they sprouted with gusto. The flats are growing beautifully, ready to plant as soon as our weed control is assured. I'm thrilled to have it named and will now try for a bulk source, I'm hoping to cover my pasture. Bet all our wildlife will love napping in it's soft bed. Walking on it feels like a big sponge. Thank you for helping me! What a happy start to my day, before the rain returns.....

Berkeley sedge is actually Carex divulsa, not a native.