花蕊，花的组成部分之一，为高等植物所拥有。依构造不同，可分为雌蕊及雄蕊。

亦称之为花皮，为被子植物保护胚珠的构造。

一朵花中的心皮数目可能单一（单一心皮）、或二个以上合生或离生。单一心皮的例子如：豆科植物，成熟后发育为豆荚（荚果）

具多数离生心皮的例子如：木兰科（白玉兰）、八角茴香科（八角）、蔷薇科（玫瑰）的植物。具多数合生心皮的种类，其心皮愈合成雌蕊，概分为柱头、花柱、子房等部。例如瓜类（瓜科），其子房或果实横剖开可见到其切面由三个部份合生而成。

In botany, a bud is an undeveloped or embryonic shoot and normally occurs in the axil of a leaf or at the tip of a stem. Once formed, a bud may remain for some time in a dormant condition, or it may form a shoot immediately. Buds may be specialized to develop flowers or short shoots, or may have the potential for general shoot development. The term bud is also used in zoology, where it refers to an outgrowth from the body which can develop into a new individual.