Glaucous (from the Latin glaucous, meaning "bluish-grey or green", from the Greek glaukos) is a botanical term (adjective) used to describe the pale grey or bluish-green appearance of the surfaces of some plants. The term glaucous is also used botanically to mean "covered with a grayish, bluish, or whitish waxy coating or bloom that is easily rubbed off" (e.g. glaucous leaves).
Examples
The epicuticular wax coating on mature plum fruit gives them a glaucous appearance. Another familiar example is found in the common grape genus (Vitis vinifera). Some cacti have a glaucous coating on their stem(s). Glaucous coatings are hydrophobic, prevent wetting by rain, and hinder climbing of leaves, stem or fruit by insects. On fruits, glaucous coatings may function as a deterrent to climbing and feeding by small insects in favor of increased seed dispersal offered by larger animals such as mammals and birds.
