Data from: Fruit evolution and diversification in campanulid angiosperms

With increases in both the size and scope of phylogenetic trees, we are afforded a renewed opportunity to address long standing comparative questions, such as whether particular fruit characters account for much of the variation in diversity among flowering plant clades. Studies to date have reported conflicting results, largely as a consequence of taxonomic scale and a reliance on potentially conservative statistical measures. Here we examine a larger and older angiosperm clade, the Campanulidae, and infer the rates of character transitions among the major fruit types, emphasizing the evolution of the achene fruits that are most frequently observed within the group. Our analyses imply that campanulids likely originated bearing capsules, and that all subsequent fruit diversity was derived from various modifications of this dry fruit type. We also found that the preponderance of lineages bearing achenes is a consequence of not only being a fruit type that is somewhat irreversible once it evolves, but one that also seems to have a positive association with diversification rates. While these results imply the achene fruit type is a significant correlate of diversity patterns observed across campanulids, we conclude that it remains difficult to confidently and directly view this character state as the actual cause of increased diversification rates.随着系统发育树（phylogenetic trees）的规模与覆盖范围不断拓展，我们获得了全新的契机，得以重新探讨长期存在的比较生物学问题——例如特定果实性状是否在很大程度上解释了被子植物支系（angiosperm clade）间多样性的差异。迄今已有多项相关研究得出了相互矛盾的结论，这在很大程度上源于分类学尺度的差异，以及对潜在偏保守的统计方法的依赖。本研究聚焦于一个更为古老且规模更大的被子植物支系——桔梗类（Campanulidae），推断主要果实类型间的性状转变速率，并重点探讨该类群中最为常见的瘦果（achene fruits）的演化历程。我们的分析表明，桔梗类的祖先类群大概率结有蒴果（capsules），后续所有果实多样性均由该干果类型的多种修饰演化而来。此外，我们还发现该支系中占据多数的瘦果类群，其成因不仅在于瘦果一旦演化便具有一定的不可逆转性，还在于该果实类型似乎与分化速率（diversification rates）呈正相关。尽管上述结果表明瘦果性状与桔梗类群的多样性分布模式存在显著关联，但我们仍认为，难以确凿且直接地将该性状视为分化速率提升的真正诱因。