茶树分为大、中、小叶种(不同于植物分类上的种)是根据茶树叶型的大小、叶脉的多少来分的。茶树叶片是典型的背腹叶,腹面(正面)即向着阳光的一面为上表面(上表皮),背面即背着阳光的一面为下表面(下表皮)。在上、下表皮之间的结构称为叶肉,中央有一条向背面突出的嵴称为主脉,沿着主脉向两侧分枝为侧脉,系典型的双子叶植物的网状叶脉。侧脉脉端近叶缘处前后相连接形成闭锁叶脉。气孔和茸毛集中分布在下表面。因此,上表面都是同形细胞,从正面观是波浪形或圆形细胞,波谷交错连接。下表皮细胞的波浪形均大于上表面。在上、下表皮细胞的外壁上覆盖着一层厚度不等的角质膜。角质膜最外一层是蜡质层,蜡质层下面是片层状的角质层,再下面接近表皮细胞壁处是果胶质与纤维素组成的介面。即使是刚开展的芽叶也具有角质层。角质层由不饱和的脂肪酸组成,不透水,不透气,具有防病虫 Tea tree is divided into large, medium and leaflet species (different from the species on the plant classification) is based on the size of the tea leaves, veins divided by how much. Tea leaf is a typical dorsal ventral leaf, the ventral (front) that is the sun on the side of the upper surface (upper epidermis), the back that is carrying the sun on the side of the lower surface (the lower epidermis). The structure between the upper and lower epidermis is called mesophyll. The central ridge has a prominent ridge on the back called the main veins. The main veins extend along both sides of the main veins as lateral veins, which are the typical veins of the dicotyledon. Lateral veins close to the edge of the formation of atresia veins. Stomata and hair are concentrated in the lower surface. Therefore, the upper surface is the same shape cells, from the front view is wavy or circular cells, troughs staggered connection. The wavy shape of the lower epidermis is larger than the upper surface. In the upper and lower epidermal cells covered with a layer of unequal thickness of the cuticle. The outermost layer of the cornea is the waxy layer, below the waxy layer is the stratum corneum, and then near the epidermal cell wall is the interface of the pectin and cellulose. Even the newly developed bud leaves also have stratum corneum. Cuticle consists of unsaturated fatty acids, impermeable, airtight, with pest control