bract
noun [ C ] biology specialized uk/brækt/ us/brækt/
苞叶，苞片（长在花的底部，形状或颜色或不同于主叶）
a type of leaf that grows from the area just below a flower and is sometimes different in shape or colour from the main leaves
Poinsettias are popular for their attractive red bracts. 一品红因其迷人的红色苞片广受喜爱。