Testa The hard dry protective covering of a seed, formed from the integuments of the ovule. After fertilization the layers of the integuments fuse and become thickened and pigmented.

• 外种皮：覆盖在种子外部的坚硬干燥的保护层，由胚珠的珠被发育形成。受精作用后珠被各层发生融合并加厚着色。