Giant Ragweed. It should be sending up a stalk that will give off a golden dust of pollen any day.

Since it is in a rural area you could probably just let it go. It is an annual that birds love the seeds of. It is a true weed whose pollen does spread very far.

Since your in the KCMO area check out Rainy Day Books for all kinds of books on plants. The local libraries are good sources for books on various weeds and wildlife plants. the Missouri Discovery centers have plastic folding pamplets for plant identification. There are several sites that will help you identify your plants. You can just put in the search field plant/weed identification. Since many of the plants are nation wide you can check many of the college and university research sites on plant identification.

Ha ha ha. I took that photo about a month ago and haven't returned to the property since. Good thing I carry Claritin in my purse for a just-in-case I need help to survive a pollen cloud.

I'm familiar with Rainy Day Books and love them because they're a small independent bookstore. I'll research the other suggestions too. Thanks for the suggestions. Ha ha ha. I had a suspicion about it being ragweed and I have no idea why.... :-)