I don't know what the source was of the Queen Anne lace that is in our lawn, because I don't remember seeing any go to seed last fall, but my lawn on one side of the house looks like solid carrot tops. Not so pleasant an aspect as a big cluster of forget-me-nots! Now that it has been mowed a couple of times they've spread out flat, and look like they're here for the duration. I go out after each rain and spend a few minutes pulling all I see in various patches, just to see what happens. I'm probably clearing the way for the next batch.