Carex feta
Carex feta, the green-sheathed sedge or greensheath sedge, is a species of flowering plant in the family Cyperaceae, native to southwestern British Columbia in Canada, and Washington, Oregon, and California in the United States. Description 
The green-bladed leaf blade is between 2.5 to 5 millimeters long, with a triangular white patch. The open inflorescence is between 30 to 80 millimeters long, which are white-green to pale gold in color. The fruit is between 3 to 4.2 millimeters in diameter, green to pale gold in color, and either ovate or wide-ovate. The fruiting time is between the months of May and August. It is like Carex fracta, but the spikelets are smaller and more distinct. It is between 50 to 100 centimeters in height. The inflorescence is elongated but with overlapping ovate spikes. The female scales are 2.7 to 3.5 millimeters long, and either straw-colored or brown. The perigynia is ovate or broadly ovate with a white tipped beak. Its chromosome number is n=33. References

feta
Flora of British Columbia
Flora of Washington (state)
Flora of Oregon
Flora of California
Plants described in 1893