Poison hemlock

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Poison hemlock leaf

Poison hemlock

Poison hemlock leaf

Poison hemlock

Poison hemlock leaves

Poison hemlock

Poison hemlock

Poison hemlock stem

Poison hemlock inflorescence

Poison hemlock

Poison hemlock leaf

Poison hemlock inflorescence

Morphology

Stem

Erect, much-branched, ribbed, glabrous, waxy, usually marked with purplish blotches.

Leaves

Alternate, long-stalked below, short-stalked above, 6 to 12 inches long, 2 to 12 inches wide, fern-like, glabrous, 3-4 times odd-pinnately compound; ultimate leaflets oblong to lanceolate, toothed or pinnately divided.

Inflorescence

Umbels, compound, 1.5 to 5 inches wide, flat to rounded, with 8-17 slender, unequal rays.

Flower

Tiny, about 1/10 inch wide, 5-parted, white; calyx teeth absent; petals 5; tips notched.

Fruit

Egg-shaped, dry, flattened, grayish brown, with 2 wavy ribbed segments; seeds 2, flattened to concave, smooth.

Ecology

Habitat

Low waste ground, thickets, roadsides, and stream banks, in moist soils.

Distribution

Throughout except southwest corner of Kansas.

Practical Information

Toxicity

All parts of this plant are highly poisonous to humans and livestock. Contact between the leaves and skin can cause nausea and blurred vision.

Additional Notes