Fig. 9
From: Heterochrony and repurposing in the evolution of gymnosperm seed dispersal units
Cone bracts from leaves: Evolutionary developmental model for the repurposing of anatomical features from vegetative leaves to reproductive bracts in Ephedra (Gnetales). Center: Diagrams of leaf development in E. tweediana (left), and E. multiflora (right) showing the shift of mature anatomy to younger stages in E. multiflora. Left: Bracts of fleshy species at Stage 1, grouped by their juvenile external leaf morphology (reduced hyaline margins), showing juvenile or mature leaf anatomy depending on the species. Right: Bracts of papery species at Stage 1, with hyper-mature external leaf morphology (widely developed hyaline margins) and mature leaf anatomy. Solid-line arrows connect stages of leaf development; broken-line arrows indicate corresponding anatomies between stages of leaf development and bract structure. Fleshy species, species with fleshy seed cone bracts; Papery species, species with papery-winged seed cone bracts. Refer to figure inset for the meaning of colors and symbols