About 50-60 of these sprung up in the last couple of days, growing 1-2 inches/day (now about 9-10 inches high) with all the alternating rain and sun we've been having. They showed up in a bed of marigolds. The leaf structure is finer, more whispy, and these are growing much faster and taller than the marigolds, which makes me suspect that they are some sort of weed. Any ideas out there. The shot was taken with an Olympus E-PL2 and a 105mm/2.8 Micro Nikkor.