Cyperus eragrostis - Tall Flatsedge

Description

You may have seen this sedge out in the riparian zones of the Bay Area and beyond.  It is very common on the West Coast of North America, and considered invasive in other parts of the world.  It's a rhizomatous spreader, so it's great for stablizing creek banks or forming a nice clump around a water feature or seep.  Leaves are very big and broad for a sedge, and the flower is very interesting looking.