Trichomes are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a plant is an indumentum, and the surface bearing them is said to be pubescent.
Flower bud of a Capsicum pubescens plant, with many trichomes
Fossil stellate hair (trichome) probably of an oak, in Baltic amber; image is about 1 mm wide.
Sticky trichomes of a carnivorous plant, Drosera capensis with a trapped insect, contain proteolytic enzymes
Glandular trichomes on Cannabis, rich in cannabinoids
An appendage is an external body part, or natural prolongation, that protrudes from an organism's or microorganism's body.
A beetle leg