Is This Plant Edible?

Judi & Carl Manning

Out for a stroll. The birds, rabbits and deer are munching on plants and berries. If they can eat it, we can too, right? WRONG, if a bird or animal eats a berry or plant, that does not mean it is edible to humans and do not assume that because part of a plant is edible, all of it is safe. Many edible plants have poisonous parts. It is believed they evolved to produce poison to protect themselves from browsing animals and plant-eating insects. Learn to identify poisonous plants in the house, yard, and neighborhood. They are everywhere – garden plants, flowers, spices, ornamental trees and house plants. Do not eat any part of an unknown plant. Teach children what plants are poisonous.

Do not eat plants or mushrooms that are picked from roadsides or other areas where herbicides or insecticides may have been used. Plants growing along the roadside may also accumulate heavy metals from vehicle exhaust (lead or cadmium). Molds or mildew growing on plants produce mycotoxins, which may make the plants poisonous. It is best not to eat moldy or rotting food.

What constitutes a poisonous plant? Any part of the plant that contains potentially harmful substances in high enough concentrations to cause chemical injury if touched or swallowed. (Pg. 1 Com. P. Pl) There are thousands of plants in the world that fall under this definition. Many medicinal plants and food plants contain chemicals that can be harmful if eaten in the right quantity. Our body can eliminate small amounts of potentially harmful substances. However, problems arise when eaten in larger concentrations.

Other substances found in plants cause skin reactions or pain, redness, blistering, swelling, or can be harmful to the eyes just from contact.

Over the centuries, plant breeders have bred plants to reduce the poisons so parts of them are edible. The potato is an excellent example. We eat the tubers that contain only traces of the bitter alkaloid solanine. The flowers, green leaves, sprouts and green, light-exposed tubers contain higher levels of alkaloid solanine and are very poisonous.

Dieffenbachia and philodendron are responsible for many poisonings in babies and toddlers. Older children may eat poisonous food as imitation food. Adult poisonings are from misidentification of ‘edible’ plants or misinformed use of herbal remedies.

Before purchasing a house plant or yard plant, find out if any part of it is poisonous or harmful. Household pets can be as vulnerable to poisoning from plants as are children, while other animals have developed special enzymes that protect them by breaking down some of the toxic compounds. Squirrels can eat Amanita mushrooms and acorns; deer can eat yew and rhododendron.

Poisonous plants are used for medical purposes because of their effects on various systems of the body. Foxglove (Digitalis) used to treat heart disease since the late 1700s, is the most widely used plant toxin. Opium Poppy gives us morphine, codeine and papaverine. May apple has anti-cancer and anti-viral properties, and taxol from the yew has anti-cancer properties. Toxic plants are used in many parts of the world and are sold in health food and herbal healing stores.

The two major types of poisons widely distributed in plants are:

Alkaloids:

Found in roots, seeds, leaves, bark and stems. Over 4,000 alkaloid compounds have been identified and are found in 20% of vascular plants and 40% of the plant families. Most are bitter tasting, potentially toxic and potentially medicinal. After ingested, alkaloids may be chemically altered by enzyme reactions in the liver, sometimes made harmless, other times made more deadly.

Some examples:

Glycosides:

Are widely distributed in plants. Many are not toxic, but a large number of them contain poisonous compounds. These compounds consist of one or more sugar molecules that combine with a non-sugar component (aglycone). There are 800 species in 80 different families that contain cyanoid glycosides. Cyanoides inhibit oxygen uptake in the cells and poisoning may occur very suddenly.

Some examples:

Other groups of toxins with varied toxic effects:

Oxalates and Oxalic Acid:

Can be eaten in moderation. Large amounts cause an accumulation of oxalic acids and salts and cause mechanical damage in the kidneys and other organs.

Some examples:

Tannins and other Phenols:

Phenols are acidic and form salts with alkaloid compounds in Poison Ivy, Poison Oak and Poison Sumac, causing serious allergic skin reactions in some people.

Resins and Volatile Oils:

Complex and diverse they occur together in mixtures called oleoresins. These affect the heart and circulatory system and are potentially deadly.

Some examples:

Did you know, that all or parts of the following plants are poisonous?