Similar species: Water Hemlock (Cicuta maculata) - leaves are quite different (not fine/feathery); shares the same habitat; also deadly poisonous. Water Parsnip (Sium suave) - leaves very different; shares the same habitat; edible. Wild Carrot (Daucus carota) - grows in dry areas; edible; smells like carrots. Japanese Hedge Parsley (Torilis japonica) - grows in drier fields. Poison Hemlock (Conium maculatum) - leaves are not narrow.
Eastern Hemlock (Tsuga canadensis) - A tree; similar in name only; no relation; not poisonous. See the Ontario Trees & Shrubs website.
Flowers: Summer; White; 5 parts (petals); Sparse, white, in an umbel (an umbrella-shaped cluster) about 1-2" wide. Individual flowers about 1/8" wide, with 5 petals and 5 stamens.
Leaves: Alternate, Toothed; Widely spaced alternate compound leaves have very narrow leaflets. Leaflets up to 3" long. Widely spaced ragged teeth. Tiny bulblets occur in the axils (where a leaflet joins the stem).
1-2 m (3-6 ft)
Widely spaced branches.Hollow.
Habitat: Wet Areas; Wet open areas such as marshes, along shores, and sometimes open swamps.