Far from it! In addition to the obvious poison mushrooms, poison oak, and poison sumac, there are about 700 other poisonous, or toxic, plants which are usually avoided by people and animals.
Common garden shrubs and plants such as azaleas, rhododendrons, mountain laurel, and foxglove are completely poisonous.
There is cyanide in cherry twigs and acid in peach leaves.
The stems and leaves of both the potato and tomato plants have poisonous compounds, as do the bulbs of the hyacinth and narcissus, and the leaves of rhubarb, the berries of mistletoe, and the bark, needles, and seeds of yews.