Not very large. They were mixed in with grasses. I didn't think to pay attention to that. There was one other smaller patch further up the trail.
Well, it looks a lot like Distichlis spicata , Calflora: Observation of Distichlis spicata This is within its elevational range, and the height is ok, though it is generally a shorter plant (but can be as tall as 80cm): Distichlis spicata Open to other ideas...
Thanks for the guess. It doesn't seem to match, in my opinion. The leaves of the one I saw seemed wider than the sea grass.
