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‘Pollination syndromes’, where convergent floral signals reflect selection from a functional pollinator group, are often characterized by physical features, yet floral rewards such as nectar may also reflect selection from pollinators. We asked whether nectar chemistry shows evidence of convergence across functional pollinator groups, i.e. a ‘chemical pollination syndrome’. We used untargeted metabolomics to compare nectar and leaf chemical profiles across 19 bee‐ and bird‐syndrome species, focusing on Salvia spp. (Lamiaceae), selected to maximize switching events between pollination syndromes.We found that independently derived bird‐syndrome nectar showed convergence on nectar traits distinct from bee‐syndrome nectar, primarily driven by the composition and concentration of alkaloid profiles. We did not find evidence for ‘passive leaking’ of nectar compounds from leaves since metabolite abundances were uncorrelated across tissues and many nectar metabolites were not present in leaves. Nectar and leaf metabolomes were strongly decoupled from phylogenetic relationships within Salvia. These results suggest that functional pollinator groups may drive the evolution of floral reward chemistry, consistent with our ‘chemical pollination syndrome’ hypothesis and indicative of selection by pollinators, but we also consider alternative explanations. In addition, our results support the notion that nectar chemistry can be decoupled from that of other tissues. 

SUMMARY Plant nuclear genomes harbor sequence elements derived from the organelles (mitochondrion and plastid) through intracellular gene transfer (IGT). Nuclear genomes also show a dramatic range of repeat content, suggesting that any sequence can be readily amplified. These two aspects of plant nuclear genomes are well recognized but have rarely been linked. Through investigation of 31Medicagotaxa we detected exceptionally high post‐IGT amplification of mitochondrial (mt) DNA sequences containingrps10in the nuclear genome ofMedicago polymorphaand closely related species. The amplified sequences were characterized as tandem arrays of five distinct repeat motifs (2157, 1064, 987, 971, and 587 bp) that have diverged from the mt genome (mitogenome) in theM. polymorphanuclear genome. The mtrps10‐like arrays were identified in seven loci (six intergenic and one telomeric) of the nuclear chromosome assemblies and were the most abundant tandem repeat family, representing 1.6–3.0% of total genomic DNA, a value approximately three‐fold greater than the entire mitogenome inM. polymorpha. Compared to a typical mt gene, the mtrps10‐like sequence coverage level was 691.5–7198‐fold higher inM. polymorphaand closely related species. In addition to the post‐IGT amplification, our analysis identified the canonical telomeric repeat and the species‐specific satellite arrays that are likely attributable to an ancestral chromosomal fusion inM. polymorpha. A possible relationship between chromosomal instability and the mtrps10‐like tandem repeat family in theM. polymorphaclade is discussed.