Found in wet areas throughout North America, water parsnip (Sium suave, Apiaceae) is a bit more intriguing than its plain appearance suggests. Although the umbels of tiny white flowers are almost indistinguishable from many other plants in the carrot family, the leaves are more interesting. Foliage details are useful diagnostic features in this family, but this plant exhibits significant foliar variation depending on growing conditions.
The once-compound leaves can be very thin and feathery when grown in water, very broad and elliptic near the base of the plant on land, or lanceolate and serrate as I found on this individual. It was growing in moist silty soil a few feet from the edge of the River Raisin here in southeast Michigan.
Like its relative Queen Anne’s lace (Daucus carota, Apiaceae) this plant is edible, and the root may present a carrot-like flavor. Eating it without certain identification, however, can be a fatal endeavor. Water parsnip bears a strong resemblance to stiff cowbane (Oxypolis rigidior, Apiaceae) and water hemlock (Cicuta maculata, Apiaceae), two of the most deadly poisonous plants in North America. These plants are very similar in appearance and growing conditions, making positive identification difficult.