Persicaria caespitosa
A common plant in moist ravines and the like in Indiana, where my pictures are from. It also occurs in the southwest.
An inflorescence near Griffy Lake on the north side of Bloomington, IN, 8/20/03.
A cauline leaf near Griffy Lake, 8/20/03.
An ocrea near Griffy Lake, 8/20/03.
Achenes near Griffy Lake, 8/20/03.