Fig. 1

Flower morphology of C. goeringii wild-type plant ‘Songmei’ and the multi-tepal mutant ‘Yuhudie’. a & b: Wild-type flower with three sepals and three petals. Two petals are similar to each other; the third is highly evolved, with an ovate to triangular shape, and is known as the labellum or lip. The male and female reproductive organs are highly fused to form a gynostemium. c: The gynostemium is replaced by newly emerged flowers in the multi-tepal mutant, and this ectopic flower continues to produce sepals and petals centripetally. d & e: Detailed compositions of two of the newly emerged flowers (indicated with red circle in c). The lips are misshapen; the gynostemia are fused to the margin of the sepals and lack an organized four-pollinia structure. Bar = 1 mm. Se, sepal; Pe, petal; Li, lip; Gy, Gynostemium