|Photos by Gene Spesard 5/25/2015|
This unusual-looking plant is in the Sedge family (Cyperaceae). I'm pretty sure it's Bearded Flat-sedge (Cyperus squarrosus) (but there are very few good photos online of plants in this family, besides Gene's above). They are often overlooked, because they aren't particularly showy. The mop heads (not the scientific term : -) are the flowers. Look for these along the creek. The flowers will turn brown, sometimes almost rust colored, as they age.
And a bonus book recommendation: A Garden of Marvels: How We Discovered That Flowers Have Sex, Leaves Eat Air, and Other Secrets of Plants by Ruth Kassinger.