Floral color plays a key role as visual signaling and is therefore of great importance in shaping plant-pollinator interactions. Iris (Iridaceae), a genus comprising over 300 species and named after the Greek goddess of the colorful rainbow, is famous for its dazzling palette of flower colors and patterns, which vary considerably both within and among species. Despite the large variation of flower color in Iris, little is known about the phylogenetic and ecological contexts of floral color. Here, we seek to resolve the evolution of flower color in the genus Iris in a macroevolutionary framework. We used a phylogenetic analysis to reconstruct the ancestral state of flower color and other pollination-related traits (e.g., the presence of nectar and mating system), and also tracked the evolution of color variation. We further explored weather floral trait transitions are better explained by environmental or pollinator-mediated selection. Our study revealed that the most recent common ancestor likely had monomorphic, purple flowers, with a crest and a spot on the fall. The flowers were likely insect-pollinated, nectar-rewarding, and self-compatible. The diversity of floral traits we see in modern irises, likely represents a trade-off between conflicting selection pressures. Whether shifts in these flower traits result from abiotic or biotic selective agents or are maintained by neutral processes without any selection remains an open question. Our analysis serves as a starting point for future work exploring the genetic and physiological mechanisms controlling flower coloration in the most color-diverse genus Iris.

花色作为视觉信号起着关键作用，因此对于塑造植物与传粉媒介的相互作用非常重要。鸢尾花（鸢尾科）是一个由 300 多个物种组成的属，以希腊彩虹女神的名字命名，以其令人眼花缭乱的花朵颜色和图案而闻名，这些颜色和图案在物种内部和物种之间都有很大差异。尽管花色差异很大鸢尾花，人们对花色的系统发育和生态背景知之甚少。在这里，我们寻求解决该属花色的进化问题鸢尾花在宏观进化框架中。我们使用系统发育分析来重建花颜色和其他授粉相关性状（例如花蜜和交配系统的存在）的祖先状态，并跟踪颜色变异的进化。我们进一步探索了气候花卉性状转变可以通过环境或传粉媒介介导的选择更好地解释。我们的研究表明，最近的共同祖先可能有单形的紫色花朵，在秋天有一个波峰和一个斑点。这些花很可能是昆虫授粉、授粉、自交亲和的。我们在现代鸢尾花中看到的花性状的多样性，可能代表了相互冲突的选择压力之间的权衡。这些花性状的变化是由非生物或生物选择剂引起的，还是通过没有任何选择的中性过程维持的，仍然是一个悬而未决的问题。我们的分析可以作为未来工作的起点，探索控制颜色最多样化的属中花色的遗传和生理机制鸢尾花。