长山核桃雌雄同株,单性花。花芽生理分化是在开花前一年的七月下旬至九月上旬,雄花生理分化较雌花大约早十至二十天。雌花芽三月中、下旬开始分化,五月下旬分化发育基本完成,历时七十天左右。全过程可分为五个时期:花芽分化初期、花序形成期、小花原基形成期、雌花总苞形成期和雌蕊形成发育期。雄花着生在一年生枝叶腋内,为柔荑花序。雄花芽于上一年秋开始形态分化,冬分化停止,来春继续分化,全过程可分为花序形成期、苞片形成期和雄蕊形成发育期。从花序原基出现到雄蕊发育完成,大约需要六个月。 Changshan walnut monoecious, unisexual flowers. Physiological differentiation of flower buds is from late July to early September of the year before flowering. Physiological differentiation of male flowers is about ten to twenty days earlier than that of female flowers. Female flower buds begin to differentiate in the middle and late March, and differentiation and development basically completed in late May, which lasted about seventy days. The whole process can be divided into five periods: the early stages of flower bud differentiation, the inflorescence formation, the formation of primordia, the formation of female involucre and the formation and development of pistils. Male flowers born in annual axillary branches, as catkin. Male flower buds began morphological differentiation in the autumn of last year, winter differentiation stopped, and continued to differentiate in spring. The whole process can be divided into inflorescence formation period, bracts formation period and stamen formation and development period. It takes about six months from inflorescence primordium to stamen development.