---

作 者 ：周勇辉1,2；刘玉萍1,2；拉本1,2；李兆孟1,2；苏旭1,2*；马永贵3

期 刊 ：植物研究 2016年 36卷 1期 页码：26-33

关键词：扇穗茅；寡穗茅；叶表皮微形态；外部形态特征；系统关系；

Keywords:Littledalea racemosa, Littledalea przevalskyi, morphology of leaf epidermis, external morphological characteristics, biosystematic relationship,

摘 要 ：通过扇穗茅属两个物种40个代表居群馆藏腊叶标本的查阅、观测及叶表皮微形态特征的综合研究显示：（1）扇穗茅具有短根状茎，圆锥花序，每小穗含6~8小花；寡穗茅无根状茎，总状花序，每小穗含3~6的小花。显然，两者隶属于不同的类群，是典型的种间关系；扇穗茅具有较原始的外部形态特征，而寡穗茅则有较高级的外部形态特征。（2）扇穗茅属两物种的叶表皮皆由长细胞、短细胞、气孔器细胞组成；同时，两物种在长细胞的长度与宽度，气孔器体积大小与分布及副卫细胞的形状，短细胞的丰缺与着生形式等性状上存在明显差异。（3）根据叶表皮性状的特征和演化趋势，对物种间系统位置和演化关系的分析表明，它们具有明显的种间间断，并且扇穗茅较原始，寡穗茅较进化，寡穗茅极有可能是由较低级的扇穗茅演化而来。这一系统进化关系与利用外部形态特征所获得的结论基本一致。

Abstract:We comprehensively studied the main character differences of 40 reprehensive populations between the nearest related Littledalea racemosa and Littledalea przevalskyi by the morphological observation and anatomical analysis of leaf epidermises. L.racemosa has short rhizomes, panicle and 6-8 florets per spikelet, while L.przevalskyi has no rhizomes, raceme and 3-6 florets per spikelet. They belong to two different species. The former is with more primitive external morphological characteristics, while the latter has more advanced ones. The leaf epidermis consists of long cells, short cells and stomatal cells. There are also differences on the anatomical characteristics of leaf epidermises including length and width of long cells, magnitude and distribution of stomatal apparatus, shape of subsidiary cells, abundance and growing form of short cells. According to the characteristics and evolutionary of trends of leaf epidermises of two species, we inferred their evolutionary positions and relationships. There is obvious discontinuity between them. Especially, L.przevalskyi is more advanced than L.racemosa, so it might derive immediately from the latter. The biosystematic relationships of these two species are corroborated by the evolutionary trend of external morphology.

---