I've sent pictures of this plant to my friend who has a native plant nursery in central OH, to the "Ask a Master Gardener" website (Ohio State U.), and finally to the company from which I had purchased Dutch white clover seed that I sowed this spring. All 4 appeared in the area where I had sown the clover, nowhere else, nor have I ever seen this plant anywhere in OH, MI, PA, VA..... Since the company was in MO, I thought there was a chance it was a Southern species that normally doesn't grow further north, but they could not help either. Although the plant looks nothing like any Amaranthus species I am familiar with or could find via Google, I cannot shake the thought that this is a member of that genus. These plants are very sturdy, 12"-18" tall, deeply rugose foliage, grew very slowly, and finally flowered several weeks ago. The flowers are pale yellow but so minute, I am unable to get a decent close-up. I could not even get a good enough look with my jeweler's loupe even to try to make a drawing of the flower in hope of getting more detail for ID. Once they flowered, I dug 3 of them up and planted them together in a large bucket, then set that into my garden cart to forestall what I expect to be a multitude of seeds from getting a start anywhere else -- although it is so distinctive I think I would not have a great deal of difficulty controlling it. But I'd just really like to know what this is. Thanks in advance for help!