Birdsfoot trefoil

Bird's-foot Trefoil or Birdfoot deer vetch:

Lotus corniculatus L. 

Driving home from Indiana University of Pennsylvania provided a new highway flower for my repertoire.  This pretty yellow flower is prevalent alongside the PA turnpike... its called birds-foot trefoil.  Planted by the Turnpike administration to prevent erosion, it is a member of the legume family and is very hardy.  It grows in poor soil (sandy or clay), populates in many ways, long tap root, and tolerates salt.  Pretty.  A weed to many but a pretty splash of color along the road.  The last picture is courtesy of the USDA website.