1. Water hemlock (Cowbane)

Grows in wet or moist ground like swamp, streambeds and ditches. All part, including roots, are poisonous. Even a small amount can lead to death.

2. Rosary Pea

This common weed found in southern Florida and Hawaii contains seeds that are so poisonous, one can kill an adult.

3. Poison Hemlock (Fool's Parsley)

All parts of this plant are dangerous, and it's easy to mix up with wild carrot or Queen Anne's Lace. The ancient Athenians reportedly used the juices of this plant to execute their prisoners, including Socrates. Death is caused by respiratory arrest and heart failure. It grows in meadows, stream banks and ditches.

4. Death Camus (Death Lily)

This plant may be mistaken for a member of the onion family, when in reality all parts of the plant are poisonous. It's found in dry, rocky areas, particularly in the western and eastern United States.

5. Castor Bean

This semi-woody plant contains poisonous seeds that may be mistaken for a bean-like food. Other parts of the plant are also poisonous. It grows in both tropical and temperate regions.

6. Iris

Irises can be found in forests, wild areas and garden landscapes. Their roots and rootstock can cause nausea, vomiting, abdominal pain, diarrhea, and elevated temperature.

7. Lily of the Valley

The leaves and flowers of this plant can cause irregular heart beat and pulse, usually accompanied by digestive upset and mental confusion.

8. Rhubarb

The leaves of the rhubarb plant can cause convulsions, coma, followed rapidly by death. (The stalks, meanwhile, are perfectly safe to eat.)

9. Daphne

A few berries from this plant can kill a child.

10. Yew

The leaves, seeds and twigs from yew are all toxic, although the foliage is more toxic than the berries. This plant can be fatal and death is usually sudden, without warning symptoms.