Morphological analysis of the early stages of disc and ray flower development in gerbera. (A) SEM images showing developing gerbera capitula when disc and ray flowers are at stages 3, 5 and 6, respectively. (B) SEM analysis comparing developmental stages 3, 5 and 6 in disc and ray flowers. Differences in stamen and in petal development between flower types start to emerge at stage 5. (C) Histological analysis of ray and disc flower primordia at stage 3 and 5. There is no difference in stamen development in ray and disc flowers at stage 3 while at stage 5 stamen development in ray flowers lag behind. Abbreviations: pa = pappus bristles, pe = petal, st = stamen, ca = carpel.