细叶型的叶上表皮气孔强烈下陷，叶肉无栅栏组织和海绵组织的区别，由木质化或栓质化细胞形成维管束鞘。
Whereas , the stomas of the upper epidermis of the thin-leave type settle strongly , there are no dividing between palisade tissue and spongy tissue in the diachyma , the vascular bundle sheath consists of lignification and suberin cells .
栓质化