Morphological characteristics,anatomical structure,and occurrence rate of bent peduncle phenomenon(BBP)were investigated in Rosa hybrida ‘Corolla’ in greenhouse.The results showed that high temperature caused a significant increase of BBP rate. The number of petals of BBP stems decreased and the flower size was smaller than those of normal stems.Moreover, the ovary also became flat.The phylloid structure appeared in No.1 sepal of BBP plant and the sepal area was enlarged,and the hairy structure of the lower epidermis disappeared and was replaced by dense stomata,and a fall of varying heights of growth positions occurred.The other four sepals were dislocated counterclockwise.The original growth position of No.1 sepal was replaced by sepalody,the structure of the epithelial cells of the sepalody changed,and the same hairy tissue as the sepal appeared in the epidermis.The vascular bundle,phloem and sclerenchyma cells of BBP peduncle changed significantly,and the peduncle bended toward to No.1 sepal.