中文摘要：

通过对蔷薇亚科蛇莓属的蛇莓[Duchesnea indica （Andrews） Focke]、委陵菜属的翻白草（Potentilla discolor Bunge）、水杨梅属的水杨梅（Geum aleppicum Jacq．）和地榆属的地榆（Sanguisorba officinalis L．）4种植物幼苗形态特征以及初生维管系统的结构研究表明：蛇莓、翻白草子叶脉序中主脉与两侧二级脉呈原始的二叉分支状，蛇莓脉序中无二级间脉，翻白草中为简单型的二级间脉；水杨梅、地榆的主脉与两侧二级脉呈进化的对生分支状，二者的二级间脉为复合型。蛇莓属幼苗子叶节区下部的中柱为原始的中始式二原型圆形单中柱，委陵菜属为较进化的外始式二原型圆形单中柱，水杨梅属为外始式二原型双钩型的单中柱，而地榆属的外始式二原型双扇型的单中柱则最为进化，并且地榆的后生木质部发达，也是进化的表现。综合叶脉数量和级数以及子叶节区下部的中柱类型分析，认为4属的演化趋势为：蛇莓属最原始，其次为委陵菜属和水杨梅属，地榆属最为进化。

英文摘要：

Morphological characteristics and primary vascular systems of Duchesnea indica （Andrews） Focke,Potentilla discolor Bunge,Geum aleppicum Jacq, Sanguisorba officinalis L. in Rosoideae were examined by tissue cleaning and paraffin sectioning, which indicated that the primary veins and bilateral secondary veins were primitively bifurcate in cotyledon venations of D. indica（Andrews） Focke and P. discolor Bunge,the venation of D. indica（Andrews） Focke did not have inter-secondary veins and the venation of P. discolor Bunge had intersecondary veins belonging to a simple type; the primary veins and bilateral secondary veins were symmetrically bifurcate in the venations of G. aleppicum Jacq,S. officinalis L. and their secondary veins belonged to a compound type. D. indica（Andrews） Focke, P. discolor Bunge,G. aleppicum Jacq,and S. officinalis L. separately had primitive mesarch diach rotundity haplosteles,more evolutionary exarch diarch rotundity hplosteles, exarch diarch double-hooked haplosteles and the most evolutionary exarch diarch double-flabellate haplosteles in the lower part of their cotyledon nodes and the exarch diarch double-flabellate haplosteles of S. officinalis L. had well-developed metaxylem, which was an evolvement indicator as well. It was thought in terms of the numbers and hierarchies of the leaf veins and the stele types in the lower part of cotyledon nodes that the evolvements of the four genera were that Duchesnea indica was the most primitive in evolvement,Potentilla and Geurn took the second place in evolvement,Sanguisorba was the most developed in evolvement.