Wax

Wax is made by honey bees to build the comb used to store honey and to protect larvae.

Did you know that plants also make wax?

Water beads on the waxy cuticle of a kale leaf (Rei) CC BY-SA 3.0

Nearly all vascular plants manufacture wax. This wax is used as part of the cuticle, or outer layer of the epidermis, of leaves, stems, and even some fruits.

Protective wax

Having a waxy outer layer reduces evaporation, making it easier for plants to hang on to the water they need. It also reduces the chance of abrasion, when plant parts rub against each other. Finally, wax makes it more difficult for pests to attack.

Wax chemistry

Wax is actually a class of fatty compounds that are insoluble in water and tend to be relatively soft at room temperature. When honey bees are between 12 and 20 days old, they develop a special gland on their belly that converts the sugars in honey into waxy flakes. The flakes are collected by other bees and chewed up before being used to make new comb. [I thought you’d want to know about that.] Plants, however, have neither the organ nor the chewing ability. Instead, plants synthesize wax out of hydrocarbons, made up of fatty acids and long chain alcohols, along with aromatics, ketones, and other chemicals. The chemical make up of a plant’s wax varies by species and geographic location.

Female bayberry plant (Hajotthu) CC BY 3.0

Carnauba palm (Tacarijus) CC BY 2.5

Plant wax candles

Carnauba wax, of shiny car and confectionary fame, is a wax made by the Brazilian palm Copernicia prunifera. A lighter colored substitute, ouricury wax, comes from the Brazilian feather palm Syagrus coronata. Several species of native bayberry (Myrica cerifera), also known as wax myrtle, and the succulent stems of candelilla (Euphorbia antisyphilitica), produce so much wax that they were used by Native Americans to make candles. In the case of bayberry, the berries are boiled until the wax separates from the plant material. After it hardens, it is removed from the soup. These candles are still made today, due to the pleasant smell as they burn. Candelilla plants are now endangered and collecting them is forbidden. Other plant waxes include castor wax, rice bran wax, and tallow tree wax.

Bayberry candles

The next time you look at a leaf or stem, take a closer look and see if wax is part of that plant’s defense system.