贺兰山岩黄耆及其近缘种的分类学研究

摘要

This paper presents a taxonomic study of Hedysarum petrovii (Leguminosae) and some related species based on field observations,examining of herbarium specimens and leaflet venation.The results showed that:Relatively stable differences between H.petrovii and its related species are shown by the morphology of floral organs.H.petrovii differs from H.brachypterum by having bractlets 1～ 2 times as long as calyx tube,standard as long as keels,while the latter has bractlets 0.5～0.8 times as long as calyx tube,standard 0.8 times as long as keels.H.petrovii differs from H.gmelinii and H.ferganense by having wings 0.3～0.5 times as long as keels,while the latter two both have wings 0.7～0.8 times as long as keels.Leaflet of H.petrovii has a venation with weak primary vein,unbranched secondary veins,many reticulated tertiary veins outside secondary vein loops,and with or without compound intersecondary veins,which is similar to that of H.brachypterum and H.gmelinii.Whereas the leaflet of H.ferganense has a venation with stout primary vein,many branched secondary veins,a little reticulated tertiary veins outside secondary vein loops,and with visibly simple intersecondary veins.Additionally,characters of leaflet venation may be informative on the discussion of intersectional relationship of the genus Hedysarum.%依据植物野外和腊叶标本形态观察以及小叶脉序观察,对贺兰山岩黄耆(豆科)及其近缘种进行了分类学研究.结果表明:贺兰山岩黄耆及其近缘种之间较为稳定的差别体现在花器官的形态方面.贺兰山岩黄耆与短翼岩黄耆的主要区别特征是小苞片长为萼筒的1～2倍,旗瓣与龙骨瓣近等长,而后者的小苞片长为萼筒的0.5～0.8倍,旗瓣长为龙骨瓣的0.8倍.贺兰山岩黄耆与华北岩黄耆和费尔干岩黄耆的主要区别是翼瓣长为龙骨瓣的0.3～0.5倍,而后二者的翼瓣长均为龙骨瓣的0.7～0.8倍.在小叶脉序特征方面,贺兰山岩黄耆与短翼岩黄耆和华北岩黄耆近似,均为小叶一级脉纤细,二级脉不分支,二级脉环外有较多网结三级脉,具少量复合二级间脉或不明显,而费尔干岩黄耆小叶一级脉粗,二级脉多分支,二级脉环外有少量网结三级脉,具明显的简单二级间脉.此外,小叶脉序特征可能在岩黄耆属组间关系的探讨中发挥作用.