鹅观草属部分种的叶表皮微形态特征及其分类学意义

在过去叶表皮实验的基础上 ,本文从鹅观草属不同组、系中新增解剖了 1 6个有代表性的种。根据这些种叶片反映的表皮微形态特征 ,进一步证实了鹅观草属共族分属以及属下类群划分的正确性 ,揭示了属中各主要类群的演化水平和系统发育关系。研究结果最后表明 :鹅观草属的半颖组最原始 ,在系统发育中它可能既派生了较进化的小颖组和大颖组 ,又派生了最进化的长颖组 ;在大颖组中 ,齿草系较原始 ,纤毛草系较进化 ,宽叶草系最进化 ,纤毛草系和宽叶草系可能相继起生于齿草系。并且 ,鹅观草属的这种进化关系同过去细胞学和形态学提供的证据是基本一致的。

LEAF EPIDERMAL CHARACTERS OF SOME SPECIES OF ROEGNERIA AND THEIR TAXONOMIC SIGNIFICANCE

representative species selected from the different sections and series of Roegneria are examined in leaf epidermal anatomy in the present paper. Based on the leaf epidermal characters displayed by these species (including Roegneria species anatomized in the past), the rationalities of the dividing and coexisting Roegneria in the tribe Triticeae and the subdivision below the genus are confirmed, the evolutional levels and systematic relationships of the major taxa in the genus also revealed. In these characters, the forms of long cell walls, the guantity and shapes of short cells, the types and density of appendages, and so on possess probably the values for differentiating sections or series; the winding of long cell walls, the increase and crescent change of short cells, the decrease of prickle hairs, the emergence of hooks and macro 1hairs, and so foth are probably parallel to the phylogenetic development of the taxa. The last results show that the sect. Goulardia (Husnot) L. B. Cai is the most primitive in Roegneria ; in the phylogenetic process, it might produce the sect. Roegneria and the sect. Ciliaria (Nevski) H. L. Yang which are more advanced than it, and also the sect. Curvata (Nevski) H. L. Yang which is the most advanced among the 4 sections. In the sect. Ciliaria (Nevski) H. L. Yang, the ser. Dentatae Nevski is the most primitive in the section, the ser. Ciliares Nevski is more advanced than the former, the ser. Platyphyllae L. B. Cai is the most advanced among the 3 series, and the ser. Ciliares Nevski and the ser. platyphyllae L. B. Cai might be derived successively from the ser. Dentatae Nevski. Furthermore, the systematic relationships of Roegneria basically are in agreement with the evidences furnished by sytology and morphology.