Look closely at burdock seedpods (Arctium sp.) and you’ll find them covered in tiny hooks.  The hooks arc away from the ball-shaped bur, ready to latch onto a passing animal.

They also latch onto us!

But that’s not the end of it.  When we try to remove the bur, it bursts open to release wind borne seeds.

Burdock is so annoying that it inspired the invention of Velcro. The man-made hooks are easiest to see after lots of use, shown below.

Learn more about the relationship between burdock and Velcro in this vintage article: Nature’s Velcro.

(photo of burdock burs on a sweater from the Plant Image Library on Flickr; click on the caption to see the original. All other photos by Kate St. John)