Two common natives known for their spring bloom and seed should be easy to find include Flowering Dogwood and Redbud. You beeter be lookin for teh dogwood berries before the birds finish them off tho.
There are many you can consider. Nandina is a nice shrub and germinates readily.
The Woody Seed Manual by the USDA can be found online here: .[url]https://www.nsl.fs.fed.us/Front%20matter.pdf[/url]. This will give you lots of good info on stratification needs (cold treatments) and cultural practices species by species.
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