Ammophila breviligulata (Poaceae)
(a) I googled common beach grass in Illinois and found the name of this plant;

(b) It is about 2-3ft tall;

(c) It is herbaceous grass;

(d) Because it is a grass, it is very hard to tell its leaf arrangement. We guess it is alternative;

(e) Leaf is simple;

(f) It has long flower spike, about 1ft in length. Because it is a grass, it is hard to tell if it is radial or bilateral;

(g) Fruits are dry and long, about 3-6mm in length.
(h) Leaves are very long and thin. Leaves can be 2-4ft long and have different colors in the front and back of leaves.