What kind of stick tight plant is this?

Question

The leaves are like that of a ragweed. The seeds are like thistle seed and they are taking over big time. They have yellow flowers and the biggest ones are between 24 and 30 inches tall. I checked the web and I don't find any that will match this plant. Any ideas what I am dealing with?

Answer 1

Shepherds needle or Bidens sp.

http://en.wikipedia.org/wiki/Bidens