The paper aims to provide a comprehensive overview of karyological and morphological variability of the Tanacetum corymbosum group in Slovakia. We estimated DNA ploidy level and relative DNA content of 530 individuals (45 populations) using DAPI flow cytometry. The morphological variation was studied by univariate as well as multivariate morphometric based on 10 morphological characters of 351 individuals (39 populations). In addition, two characters were measured on 120 achenes (six populations). Flow cytometry analyses confirmed two predominant cytotypes within T. corymbosum group in Slovakia: diploids corresponding to T. clusii and tetraploids corresponding to T. corymbosum. Further, we recorded rare occurrence (1.3% of the dataset) of minority cytotypes – presumable triploids and pentaploids, probably originating from fusion of reduced and unreduced gamete in single species populations. One triploid plant found at the only one locality with common occurrence of T. clusii and T. corymbosum is most probably of hybrid origin. Morphological analyses showed that T. clusii and T. corymbosum could not be clearly distinguished by either of the studied characters but by combining all studied quantitative characters of stem, leaves, and corymbs, it was possible to correctly classify more than 91% of the plants. Number and size of stem leaves as well as capitula, and coloration of the margin of the involucral bracts were identified as the most useful for their determination. Based on revealed karyological and morphological differentiation of T. clusii and T. corymbosum, we favour to recognize them as two separate species rather than subspecies. A key for identifying native Tanacetum species in Slovakia is presented.

本文旨在全面概述斯洛伐克Tanacetum corymbosum组的核学和形态变异性。我们使用 DAPI 流式细胞术估计了 530 个个体（45 个种群）的 DNA 倍性水平和相对 DNA 含量。基于351个个体（39个种群）的10个形态特征，通过单变量和多变量形态测量研究了形态变异。此外，还测量了 120 个瘦果（六个种群）的两个特征。流式细胞术分析证实了斯洛伐克T. corymbosum组内的两种主要细胞类型：对应于T. clusii 的二倍体和对应于T. corymbosum 的四倍体. 此外，我们记录了少数细胞型的罕见发生（数据集的 1.3%）——推测的三倍体和五倍体，可能源自单一物种种群中减少和未减少配子的融合。在唯一一个与T. clusii和T. corymbosum共同发生的地方发现的一种三倍体植物很可能是杂种来源。形态学分析表明T. clusii和T. corymbosum不能通过所研究的任何一个性状来明确区分，但通过结合所有研究的茎、叶和伞房花序的数量性状，可以正确分类超过 91% 的植物。茎叶和头状花序的数量和大小以及总苞片边缘的颜色被认为是最有用的。基于揭示的T. clusii和T. corymbosum 的核学和形态分化，我们倾向于将它们识别为两个独立的物种而不是亚种。介绍了识别斯洛伐克本地Tanacetum物种的关键。