View photos of the edible plant, Panicum capillare (Panicgrass), profiled in the Wild Edible Series: California: Vol 1, Kansas, Nevada, New Mexico: Vol 1, and others.

A passage from Wild Edible Plants of Kanas:

It’s a plant of moist/disturbed soils. Look for it around ditches, dirt roadsides, dam and reservoir areas, and field edges.

A passage from Wild Edible Plants of Nevada:

Strip the seeds from the stems by pinching low on the bunch and pulling towards the top. And/or the panicles can be rolled between the hands. Give the seeds (and small stems) a vigorous hand–rubbing and then winnow them in a light breeze (or fan set on low).