中文摘要：

长江中下游平原和东北三江平原是我国最大的两个冲积平原,其内河流、浅水湖泊和沼泽众多,菱属植物种类丰富。本研究基于对这两个区域中菱属野生植物的广泛调查,采集其居群42个,分属于9种（细果野菱、四角刻叶菱、四角菱、菱、丘角菱、东北菱、四角大柄菱、八瘤菱、四瘤菱）,3变种（四角矮菱、南昌格菱、短四角菱）。进一步对采集的菱属野生植物16个分类性状进行测量和统计,并对其形态学性状的可塑性变异及分类学价值进行分析和评价。结果显示：依据菱角的果体大小、果喙性状可以将采集的菱属野生植物划分成两个类群,其中A类群仅包括细果野菱和四角刻叶菱,而其余的菱属植物7种3变种组成B类群;对有腰角组（5种2变种）的腰角性状进行聚类分析,也可将细果野菱和四角刻叶菱与其他菱属植物区分开来;而瘤突、叶和气囊性状的分类价值有限。说明果体大小、果喙和腰角性状的形态学特征是菱属植物分类和鉴定的主要依据。

英文摘要：

With many lakes,rivers,and marshes,the middle-lower Yangtze and Sanjiang plains are the two largest alluvial floodplains in China. After extensive surveys of the two areas,wild species of Trapa were found to be abundant in the two plains,and included 42 populations consisting of nine species（ T. maximowiczii,T. incisa,T. quadrispinosa,T. bispinosa,T.japonica,T. manshurica,T. macropoda,T. octotuberculata,and T. mammillifer） and three variants（ T. natans var. pumila,T. quadrispinosa var. yongxiuensis,and T. pseudoincisa var.nanchangensis）. The morphological plasticity and taxonomic significance of the wild species of Trapa were evaluated using 16 classification characters. Results showed that：（ 1） the species and variants of Trapa were divided into two groups based on nut size and snout.Group A contained two species,T. maximowiczii and T. incisa; the remaining seven species and three variants were included in Group B;（ 2） for the five species and two variants with pseudohorns,cluster analysis of the morphological characters showed that T. maximowicziiand T. incisa were clustered together and separated from the other species and variants; and,（ 3） low taxonomic values were found for the characters of tubercles on nuts,leaves and petiole swellings. In conclusion,nut size and the morphology of the snout and pseudohorn offered the best diagnostic criteria for the classification of Trapa.