Trichomes are hair-like outgrowths which occur on the surface of some plants and protists. In cannabis plants, trichomes are the hair-like strands, in the heads of which THC and other chemically active products occur. Like THC itself, trichomes are believed to be part of the evolved mechanism plants use to defend themselves from herbivores and other environmental damage-causing factors. Organelles produced by the plant called vacuoles and plastids contain phenols, a chemical compound similar to alcohol, and hydrocarbons called terpenes. These substances make their way up the trichome stalk and combine inside the secretory cavity into a fibrous mat. This concentrated mat is hit by Ultraviolet-B light waves, causing the creation of cannabinoids. As the trichomes contain all the psychoactive components of the cannabis plant, their care and extraction are important factors for the cannabis breeder, and they are harvested in a variety of ways (see Finger Hash, Hashish, Ice Hash.) Although plants with high level of trichomes are prized (as much for their aesthetic qualities as for their supposed potency) the amount of active chemical in the trichomes themselves varies highly, and thus the trichome-rich, ‘glassy’ appearance of a cannabis plant is not actually a signifier of psychoactive strength.
From the Greek t????µa – trikhoma, meaning ‘hair’