Devil's Beggartick

Maybe you recognize this plant? If not, you might recognize its seeds when your pets get them in their fur.

 The plant is Devil's Beggartick (Bidens frondosa). It is native to North America and often found in fields and along roadways.

It propagates from self-seeding. Thoreau wrote in his journals about seeds: "If in October you have occasion to pass through or along some half-dried pool, these seeds will often adhere to your clothes in surprising numbers. It is as if  you had unconsciously made your way through the ranks of some countless but invisible lilliputian army, which in their anger had discharged all of their arrows and darts as you, though none of them reached higher than your legs."

The plant's medicinal history was that it was used for making infusions that treat irritation, inflammation and bleeding of the urinary tract, in addition to other things.

You can read more about this plant on the Weed Science Society of America website.