Trichomes by definition 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.
The cannabis plant produces resinous hair-like structures which erect from the flower of the bud. Marijuana trichomes contain THC which house the psychoactive effects of weed and when activated produce a euphoric “high”.
The head of a cannabis trichome starts filling with clear liquid. Over time it turns milky white and then amber. When most trichomes are milky-white and a few are amber, the plant is ready to harvest.