Fig. 3

Artedia squamata. Morphogenesis of the umbel (A–E, I) and ray flowers (F–H). A Large and flat, naked FUM fractionates peripheral umbellet meristems as common primordia with involucral bracts. B Umbellet meristems follow in centripetal order. Note how involucral bracts enforce the change in peripheral umbellet meristems’ geometry. C Peripheral umbellets fractionate two common ray flower/involucel primordia. Central umbellets are developmentally retarded. D Umbel becomes cup-shaped. The naked centre of the FUM persists. E Pentagonal, mirror-imaged ray flower meristems develop in proximity to each other. F Ray flower meristem fractionating first floral organs in group-like pattern. G Ray flower meristem before gynoecium initiation. Note enlarged abaxial petals (pt 1) with interpetalous sepal and bifacial symmetry of the meristem. H Late-stage ray flower showing distinct, enlarged petal lobes (Artedia-type zygomorphy). I Late-stage of umbel development. For colours and abbreviations, see Fig. 2. Scale bars = 100 µm