Highway # 9 at Overflowing River, North of Hudson Bay, SK
There are 8 to 12 longitudinal ridges connected by longitudinal rows of short horizontal ridges call trabeculae. Note the scale; the achene is very small. This picture was taken with a trinocular microscope. The setup is shown below. The achene is the white speck just below the "9" on the ruler. All other pictures of this species were taken with a 60 mm macro lens.