Pennycress seedpod / Thlaspi arvense

I've always liked the dried, flattened seedpods of Pennycress. This common plant, also known as Stinkweed, forms dense stands on disturbed soil. Regarded in restoration and landscaping as a useful volunteer cover crop. Not invasive, but may exclude native colonizers of disturbed soil. A prolific producer of very persistent seed. It has developed herbicide resistance at a few Alberta sites. This macro shot was taken on 17 July 2013, in the pond area at Burnsmead, Fish Creek Park.

www.anpc.ab.ca/wiki/index.php/Thlaspi_arvense