Weed identification - the answers

Thank you to the many folks who helped identify the following seven plants.

Ragweed. I did my neighbors with allergies a favor and pulled it.

Perhaps a type of mustard or shepherds purse, but as Molly wrote, "Anything that flowers that fast is suspect." Math and Tamara think it's field pennycress. I pulled it, but oddly, before ID'ing it, I bought a pennycress plant from a farmer's market herb stall. Unsure, I pulled it.

Yarrow, an insect attractor, tends to be on permaculture lists of "good plants." I did get one warning that it spreads and is hard to get rid of once it's established. I decided to leave it.

ID'd as pigweed or redroot, amaranthus. Most people thought it was edible, though one said no. I pulled it. 

  

Zinnia - an annual flower from seed I threw in with the clover just to see what would happen. The largest of these plants have a flower starting, I left it.

Purslain - edible and delicious according to most people. I left it.

This domestic number is fast outgrowing my patience. I'm going to hack it back this weekend.