栒子属（Cotoneaster Medikus）植物叶表皮微形态特征及其分类学意义

在光学显微镜和扫描电镜下，对栒子属（Cotoneaster Medikus）2组15种植物的叶表皮特征进行了观察，发现疏花组（Sect. Cotoneaster）植物叶表皮细胞多为多边形，垂周壁一般为平直—弓形，气孔均为无规则型；单花组（Sect. Uniflos）植物叶表皮细胞常不规则型，垂周壁多浅波状，气孔除无规则型（anomocytic）外还兼有十字型（staurocytic）、四分体型（tetracytic）和等三体型（isotricytic）。依据气孔周围角质膜特征等叶表皮性状，把15种植物分为W型、S型和I型，其中W型是S型的特化类型，疏花组的种类为W型或S型，单花组的种类为I型。叶表皮微形态特征可以为栒子属植物组及种的分类学处理提供解剖学资料。

Characters of Leaf Epidermis and Their Taxonomic Significance in Cotoneaster Medikus

The leaf epidermis of 15 species, representing two sections of the genus Cotoneaster was investigated using light microscopy(LM) and scanning electron microscopy(SEM). In Sect. Cotoneaster, leaf epidermal cells are usually polygonal in shape, straight to arched in pattern of anticlinal wall, and the stomata are anomocytic. While in Sect. Uniflos, leaf epidermal cells are usually irregular in shape, repand or sinuous in pattern of anticlinal wall, the stomata are anomocytic, and staurocytic, tetracytic, isotricytic besides. The fifteen species can be divided into three types: type W, type S, and type I, according to the characters of cuticular membrane surrounding the stomata and the other epidermal characters. Type W is an exceptional type S. Plants of Sect. Cotoneaster investigated here are type W or type S, while plants of Sect. Uniflos belong to type I. The characters mentioned above are of much significance in delimiting sections and species in Cotoneaster.