Fan Leaf Shape

Fan leaf shape refers to the characteristic morphology of cannabis plant foliage, where leaves radiate outward from a central petiole in a palmate (hand-like) pattern. This trait is controlled by multiple genetic factors and exhibits variation across cultivars—commonly ranging from narrow, elongated leaflets to broader, rounder configurations. Fan leaf structure is one of the most visually distinctive features in cannabis taxonomy and has been informally used by cultivators for decades to assess plant vigor and phenotypic expression. The number of leaflets per fan (typically 5–13) and their relative width vary consistently within stable lineages, making leaf morphology a useful reference point in breeding records. Understanding fan leaf architecture helps breeders evaluate genetic stability, predict growth patterns, and document lineage characteristics in their breeding work.

Breeders track fan leaf shape as a phenotypic marker for genetic consistency and as a secondary trait linked to broader plant architecture. Stable fan leaf expression within a family often indicates predictable growth structure and can serve as a visual reference for identifying true-breeding lines or F1 hybrid vigor.