Desmodium canadense in bloom

Desmodium canadense, known in English as "showy tick trefoil", "Canada tickclover", "beggar's lice", or "Canadian tick-trefoil" and in French as desmodie du Canada, is a perennial native to eastern Canada and northeastern and central US.

This picture does not show showy tick trefoil at its prime; for photos where it actually looks showy, see the Desmodium canadense page at Missouri Plants, which includes some amazing closeups of individual flowers. The "tick" in the English common name refers to the seeds, which, like ticks, cling to animals' fur (and peoples' clothing).

I photographed this plant at High Park.