Perhaps Corydalis flavula.

I'll wager that it's pretty Virginia creeper, a non poisonous vine. Here is a link that might be useful:

Thanks on the ID of the first one. I further IDed it to Cyperus Retrorsus The second Is very hearty. The stem resembles a twig, and it takes quite a bit of force to pull that tap root out of the ground. Could it be some type of wild shrub? Edit: Found this vacant lot with 3 foot tall versions of this stuff... Check the links and pics This post was edited by kb850 on Sat, May 11, 13 at 17:50

Thanks for those suggestions! By searching those I found this key: http://fm1.fieldmuseum.org/keystonature/eupatorium/index.html Which seems to differentiate them based on altissima having 3 prominent veins and often being unserrated. That leads me to think mine is E. serotinum? I have so much to learn with plant ID; I had noticed that the flowers looked much like my chocolate Joe Pye, but the leaves were so different from that and my other Eupatoriums.