Summary Semelparous annual plants flower a single time during their 1‐yr life cycle, investing much of their energy into rapid reproduction. By contrast, iteroparous perennial plants flower multiple times over several years, and partition their resources between reproduction and persistence. To which extent evolutionary transitions between life‐cycle strategies are internally constrained at the developmental, genetic and phylogenetic level is unknown. Here we study the evolution of life‐cycle strategies in the grass subfamily Pooideae and test if transitions between them are facilitated by evolutionary precursors. We integrate ecological, life‐cycle strategy and growth data in a phylogenetic framework. We investigate if growth traits are candidates for a precursor. Species in certain Pooideae clades are predisposed to evolve annuality from perenniality, potentially due to the shared inheritance of specific evolutionary precursors. Seasonal dry climates, which have been linked to annuality, were only able to select for transitions to annuality when the precursor was present. Allocation of more resources to above‐ground rather than below‐ground growth is a candidate for the precursor. Our findings support the hypothesis that only certain lineages can respond quickly to changing external conditions by switching their life‐cycle strategy, likely due to the presence of evolutionary precursors.

The grass family Poaceae is among the largest and most successful plant families, both ecologically and economically. It covers a wide geographic, climatic, and ecological range and contains many of the world's most important crops including wheat, barley, rice, maize, and sorghum, as well as many forage and biofuel species. Both wild and cultivated grasses are diverse in areas that regularly experience cold and freezing as well as high seasonality, harsh winters, and short growing seasons. Grasses growing in these environments have evolved an arsenal of strategies to tolerate or resist cold stress, or to escape the cold by phenological adjustments. Here, we review the current knowledge of cold adaptations in grasses synthesising across the disciplines of stress physiology, genetics, metabolomics, ecology, and evolution, in both wild and cultivated species. Specifically, we explore what is known about molecular and physiological cold stress responses, how these might have evolved and their role in shaping diversification and distribution patterns of grasses. We argue that integrating insights from multiple disciplines will further our understanding of cold adaptation.