One photo compares spikes of C. inops heliophila (left) and C. pennyslvanica (right), and another compares perigynia with C. inops heliophila top and C. pennsylvanica bottom. A good field character is that C. inops heliophila foliage is stiff/erect, not flexuous like C. pennsylvanica. Also the most distal staminate scales are relatively acuminate in C. inops heliophila, and the perigynium beaks are longer.
Unsure of id. Saw this while driving and pulled over to take some quick cell phone pics. Hundreds of plants in full bloom along hwy 14.
Sand laid down over culvert on trail