Apium lineare

About

Sium suave, the water parsnip or hemlock waterparsnip, is a perennial wildflower in the family Apiaceae. It is native to many areas of both Asia and North America. The common name water parsnip is due to its similarity to parsnip and its wetland habitat. The alternate common name hemlock waterparsnip is due to its similarity to the highly poisonous spotted water hemlock.

Summary from Wikipedia