Capitate Sessile Ratio

Capitate-sessile ratio (CSR) describes the relative abundance of two main trichome morphologies on cannabis flower: capitate-stalked trichomes (mushroom-shaped heads on visible stalks) versus sessile trichomes (glandular heads sitting directly on the leaf surface without stalks). Breeders and researchers use CSR as a microscopic classification tool to differentiate cultivar phenotypes and track genetic expression across lineages. Higher capitate-stalked ratios are often associated with cannabinoid production, while sessile-dominant profiles may indicate different secondary metabolite distributions. CSR measurements require magnification (typically 40–100×) and represent one objective method for trichome profiling alongside visual assessment and chemical analysis. This classification remains relevant in breeding programs tracking resin gland development and consistency across generations.

Breeders monitor CSR when selecting for resin production consistency and cannabinoid expression. Stable CSR phenotypes help predict trichome density and composition across seed populations, supporting reproducibility in cultivar stabilization.