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Summary: The cannabis leaf is iconic, but it is the flowers of cannabis that are consumed for the psychoactive and medicinal effects of their specialized metabolites. Cannabinoid metabolites, together with terpenes, are produced in glandular trichomes. Superficially, stalked and sessile trichomes in cannabis only differ in size and whether they have a stalk. The objectives of this study were: to define each trichome type using patterns of autofluorescence and secretory cell numbers, to test the hypothesis that stalked trichomes develop from sessile‐like precursors, and to test whether metabolic specialization occurs in cannabis glandular trichomes. A two‐photon microscopy technique using glandular trichome intrinsic autofluorescence was developed which demonstrated that stalked glandular trichomes possessed blue autofluorescence correlated with high cannabinoid levels. These stalked trichomes had 12–16 secretory disc cells and strongly monoterpene‐dominant terpene profiles. In contrast, sessile trichomes on mature flowers and vegetative leaves possessed red‐shifted autofluorescence, eight secretory disc cells and less monoterpene‐dominant terpene profiles. Moreover, intrinsic autofluorescence patterns and disc cell numbers supported a developmental model where stalked trichomes develop from apparently sessile trichomes. Transcriptomes of isolated floral trichomes revealed strong expression of cannabinoid and terpene biosynthetic genes, as well as uncharacterized genes highly co‐expressed with CBDA synthase. Identification and characterization of two previously unknown and highly expressed monoterpene synthases highlighted the metabolic specialization of stalked trichomes for monoterpene production. These unique properties and highly expressed genes of cannabis trichomes determine the medicinal, psychoactive and sensory properties of cannabis products. Significance Statement: The unique monoterpene‐rich cannabis stalked trichomes that determine the medicinal, psychoactive and sensory properties of cannabis flowers develop from sessile‐like intermediates. [ABSTRACT FROM AUTHOR]

• In this Review Article we highlight recent progress in research on terpene metabolites in cannabis. • This includes highlighting issues related to claims of medicinal properties of cannabis terpenes. • We also highlight issues related to so-called 'strains' and the need to establish properly genotyped cannabis varieties for research and use in the industry. • We highlight areas that require future research, including expanded genotyping and genetic transformation. Cannabis sativa (cannabis) produces a resin that is valued for its psychoactive and medicinal properties. Despite being the foundation of a multi-billion dollar global industry, scientific knowledge and research on cannabis is lagging behind compared to other high-value crops. This is largely due to legal restrictions that have prevented many researchers from studying cannabis, its products, and their effects in humans. Cannabis resin contains hundreds of different terpene and cannabinoid metabolites. Many of these metabolites have not been conclusively identified. Our understanding of the genomic and biosynthetic systems of these metabolites in cannabis, and the factors that affect their variability, is rudimentary. As a consequence, there is concern about lack of consistency with regard to the terpene and cannabinoid composition of different cannabis 'strains'. Likewise, claims of some of the medicinal properties attributed to cannabis metabolites would benefit from thorough scientific validation. [ABSTRACT FROM AUTHOR]