What is the nature of petals in Caryophyllaceae? Developmental evidence clarifies their evolutionary origin

摘要

Floral development is a powerful tool to infer homologies of floral organs and to understand floral evolution. Caryophyllaceae is a major family of core Caryophyllales that possesses petal-like structures (petaloids) with a great diversity in shape. The main purpose of this study is to determine the nature of the second whorl of floral organs in Caryophyllaceae. Mainstream views consider ancestors of Caryophyllaceae as apetalous and interpret petals as centrifugally derived staminodial appendages. This hypothesis, based on morphological similarities of petals with stamens and previous ancestral state reconstruction, is tested here.