Compositae (Asteraceae), also known as the sunflower family has evolved to become the most diverse and advanced angiosperm family. However, with high diversity, taxonomic complexities also arise at several levels. A reliable tool in resolving such taxonomic conundrums in this family is the characteristic fruit of Compositae known as “cypsela.” While most of the previous cypsela-based studies have focused on specific tribes and species of Compositae, in this study, we shift our focus to the genus level and seek a broader understanding of the taxonomic relationships that prevail in this family. In order to achieve this, we sampled 25 genera of Compositae and subjected them to qualitative and quantitative analysis to resolve them into groups based on the degree of similarity. This study was conducted by employing light microscopy techniques for gathering the qualitative and quantitative morphological data of the cypselae. The qualitative data were collected on six key morphological characteristics—shape, color, base, surface ornamentation, ribs, and pappus types for all the members. These data were used to yield an artificial dichotomous key to genera for the 25 members. The quantitative data on dimensions (length, breadth) of the entire cypsela as well as the pappus and ribs were subjected to principal component analysis, to understand the covariance among these variables. Hierarchical clustering followed by dendrogram construction was used to visualize the patterns of correlation within the samples and make taxonomic conclusions. The resulting dendrogram showed four closely related clades that consisted of 23 out of the 25 members whereas 2 members emerged as outgroups. The results of this study commensurate with DNA-based resolution of the concerned Compositae members, hence highlighting the reliability and significance of both light microscopy and morphology-based studies that seem to be fading away otherwise.

中文翻译：

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通过 LM 研究菊科部分成员的 Cypsela 多样性及其分类学意义

菊科（Asteraceae），也被称为向日葵科，已经进化成为最多样化和最先进的被子植物科。然而，由于高度多样性，分类学的复杂性也出现在几个层次上。解决该科中此类分类难题的可靠工具是被称为“cypsela”的菊科特色果实。虽然之前大多数基于 cypsela 的研究都集中在菊科的特定部落和物种上，但在本研究中，我们将重点转移到属水平，并寻求更广泛地了解该科中普遍存在的分类关系。为此，我们对菊科25个属进行了定性和定量分析，根据相似程度进行分组。这项研究是通过采用光学显微镜技术收集 Cypselae 的定性和定量形态数据进行的。定性数据收集了所有成员的六个关键形态特征——形状、颜色、基部、表面装饰、肋骨和冠毛类型。这些数据被用来为 25 个成员生成一个人工的二分键。整个cypsela以及冠部和肋骨的尺寸（长度，宽度）的定量数据进行主成分分析，以了解这些变量之间的协方差。使用层次聚类和树状图构建来可视化样本内的相关性模式并得出分类结论。得到的树状图显示了 4 个密切相关的进化枝，由 25 个成员中的 23 个组成，而 2 个成员作为外群出现。这项研究的结果与相关菊科成员基于 DNA 的分辨率相称，因此突出了光学显微镜和基于形态学的研究的可靠性和重要性，否则这些研究似乎正在逐渐消失。