Cannabis leaf surface. Coloured scanning electron micrograph (SEM) of the surface of a cannabis (Cannabis sativa) leaf. The pointed hairs are called lithocyst cells. They contain cystolyths (calcium carbonate crystals). Glandular cells called trichomes are present in the foreground. They are of two types: capitate trichomes have stalks, whereas peltate trichomes are rounded and closer to the leaf surface. Trichomes secrete a resin containing tetrahydrocannabinol. The resin is the source of a euphoriant drug. Magnification unknown.