Calyx

In general botany, the calyx is the outermost floral whorl composed of sepals. In cannabis culture, "calyx" is routinely used to denote the small, tear-drop-shaped, trichome-dense structure enclosing the ovary and from which the stigmas emerge — but this is a misnomer. Cannabis sativa flowers bear only a vestigial, membranous perianth; the structure cultivators call the "calyx" is anatomically the perigonal bract (also termed bracteole or perigonium) — a modified leaf-like organ, not a sepal whorl (Small 2015; Spitzer-Rimon et al. 2019; McPartland et al. 2020). The perigonal bract develops from a common meristem with the female flower, enlarges to envelop the developing achene, and bears the highest density of capitate-stalked glandular trichomes on the plant, making it the principal site of cannabinoid accumulation (Spitzer-Rimon et al. 2019; Livingston et al. 2020). Clarke's (1981) widely cited "calyx-to-leaf ratio" (a density index for cured flower) should properly be called the perigonal-bract-to-leaf ratio (McPartland et al. 2020). Etymology: Greek kalyx ("husk, cup"), Latin calix ("cup"). Synonyms / correct terms: perigonal bract, bracteole, perigonium. ⚠️ Disputed: cannabis-culture misnomer vs. correct botanical anatomy. → See also: Trichome, Pistil, Sugar leaf.