Thefirst three parts all formed five primordia,and then respectively deve-loped into calyx(calyx tube and five upper part lobes),corolla(corollatube and five upper part lobes)and five stamens.

• 前三者在分化早期；均形成五个原基；以后分别发育成花萼(萼管及其上部的五个裂片)、花冠(花冠筒及顶端五浅裂片)及五个雄蕊.