Golden Ragwort, Senecio aureus

That looks to me like Garlic Mustard. If so it should have a distinctive garlic smell. You'll want to get rid of it completely.

I agree with ladyslppr. Senecio has two different types of leaves: the bottom ones are fairly close to what the photos show, but the leaves sparsely located on the flowering stems are very different, somewhat toothed. I don't see that in photos. As for garlic mustard, it is high on the invasive list although I only saw it for the first time this spring...and then saw fields of it in the NC mts. Both have already bloomed in NC by now, if that is any help. GM has white blooms, and the senecio has yellow.

Thanks to all of you. There's no distinct odor, and the leaves appear to have a different shape and habit from the diagram on PLANTS, so I think I can eliminate Garlic Mustard. I'll probably have to wait for flowers to make a definite determination.

Thanks,
Jeff Cagle

yes, if it Gm then weed wack it down and pull it out, that way it cannot set seed

"most of my sources focus on flowers".
Now you know why. Either flower or seedhead makes ID much easier. Both Garlic Mustard & Golden Ragwort bloomed last month.
Do you by any chance live in or near Montgomery Co? If so, think about going to the meeting of the Maryland Native Plant Society next week. They have botanists there that will know your plant at a glance.
Sam

Here is a link that might be useful: Maryland Native Plant Society