Common Water Hemlock (Spotted Cowbane)
A tall, vigorous perennial plant with many leafy branches, usually streaked or spotted with purple, hairless. Flowers minute, with 5 petals, white, in compound umbels 2–5 inches across, surmounting the leafy shoots. Blooms May–September. Leaves compound, the lower ones to 1 foot long. Leaflets linear to lanceolate, ovate with coarse teeth, but sometimes without them.
Because this plant is extremely toxic, while other close relatives are considered edible, correct identification is critical for anyone wishing to eat "wild edibles." Water hemlock has doubly-compound leaves and the leaflets are large and rarely lobed. The veins that extend laterally from the leaflet midveins end mostly in the sinuses between the teeth (and not at the points of the teeth). If you are inexperienced with plant identification, it is best to consider all wild members of the carrot family as potentially fatally toxic.