Fumaria species have those long seed leaves followed by the feathery leaves. Which ones are likely in your neck of the woods?

or something from the apiaceae family.

Not getting an Apiaceae vibe from these, Campanula. Fumaria would fit the slightly hairy stems. They look a lot like the Fumitory seedlings we get over here.

Floral, the five Fumaria species that are possible here include capreolata, densiflora, officinalis, parviflora, and vaillantii. These are all non-native and rare, with none reported in Arkansas to date. I did take another photo of plants about 50 yards distant that I thought were in the Parsley Family. Now, I'm wondering if they were more mature examples of the same species. They had many stems from the base, with each stem about 10 inches long. An example follows.

With that many seedlings in a patch are there any old stems or seed heads around which might help?

I did move leaves and debris to see if there were any remnants of mature plants with the seedlings. None were found.

I also searched for a list of dicots with shortly persistent cotyledons, but didn't have any luck. It looks like this will be another one to add to my 2015 list. I keep a record of unusual plants, and return there the following year to determine species. It provides some level of entertainment during my winter walks. Thanks for your help.

Queen Anne's lace?

Thanks, esh. I'm leaning toward that one, or a Chaerophyllum.