根据叶表皮微形态特征试论新麦草属、芒麦草属和三柄麦属间的系统关系

观察了禾本科新麦草属、芒麦草属和三柄麦属主要代表种的叶片表皮形态学特征，总结了三属植物叶表皮结构的异同，探讨了叶表皮特征的分类学意义。同时，根据三属植物叶表皮性状的演化趋势，分析了各属的演化关系和系统位置。结果表明，新麦草属最原始，芒麦草属较进化，三柄麦属最高级；新麦草属可能直接派生了较进化的芒麦草属，并在芒麦草属的基础上进而产生了最高级的三柄麦属。三柄麦属、芒麦草属和新麦草属的这一系统关系同它们外部形态上三联小穗的演化趋势是相互印证的。

The Biosystematic Relationships among Psathyrostachys,Critesion and Hordelymus Based on the Micromorphological Characteristics of Leaf Epidermis

The leaf epidermises of the major species of Psathyrostachys, Critesion and Hordelymus in Poaceae were examined, their similarities and differences on the leaf epidermis were summarized, and the taxonomic significance of leaf epidermal features among them also were discussed. Furthermore, according to the evolutionary trends of leaf epidermal characters of the three genera, their evolutionary positions and relationships were inferred as well. The results show that the genus Psathyrostachys is the most primitive one among the three genera, the genus Critesion is slightly more advanced than the former, and the genus Hordelymus is the most advanced of them; the genus Psathyrostachys might produce immediately the genus Critesion, whereas the genus Hordelymus might derive immediately from the genus Critesion. The biosystematic relationships of the three genera are corroborated by the evolutionary trend of trispikelet in the external morphology.