Morphological differences between thorns, spines, and prickles
Trichomes are specialized epidermal tissue
Glandular vs Non-Glandular
Glandular trichomes: have cells that can secrete or store specialized chemicals compounds (secondary metabolites). Above, Urtica dioica stinging nettle has glandular trichomes that pierce your skin, and the pressure of contact injects a mixture of irritating chemicals (including histamine, formic acid, acetylcholine, and serotonin)
Non-glandular trichomes: lack this secretory ability and often serve as physical barriers or for insulation. Above Cannabis sativa with hair-like non-secretory trichomes that do not produce cannabinoids or terpenes. Below Cannabis sativa with glandular capitate trichomes storing secondary metabolites in a cuticle at the apex




















