The long tail on the pods is unique to the Radishes.  I've let various Daikon cultivars mature and they all had pods or siliqua like those.  Seems hard to believe its not pea sized seeds in those pods!  

There may be other plants/wildflowers that will have a similar seed pod; crotalaria, baptisia, etc., that might show up later in summer/fall, but those pods will be 'fatter' and clustered together along the stalk and stems.