“Parsnip flowers are a wonderful nectar source for flies and other small insects, and parsnips are a host plant for gorgeous black swallowtail caterpillars, which mature as one of our handsomest butterflies….
…The tastiest way to diminish any threat from the sap of the tall second-year plants is to dig and eat the roots of the first-year plants after frost. These are just as edible as their domesticated cousins, though our daughter’s infant name for them -“Rattails” -suggests their average size, and it’s important not to eat any of the related poisonous species, such as water hemlock (an Internet search, or any edible plant guide will give the identifying characteristics).”
From an article in The Recorder 10/6/1