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Summary Nectar, a vital mediator of plant–pollinator interactions, exhibits remarkable chemical diversity beyond sugars, including reactive oxygen species and specialized metabolites such as pigments. Colored nectars, present in over 70 species, function as visual signals, inhibitors of microbial growth, or nutritional rewards, underscoring their ecological importance. Reactive oxygen species contribute to pigment formation and nectar stability, highlighting their dual roles in nectar chemistry and defense. Advances in analytical techniques and interdisciplinary research have highlighted the complex interplay between nectar composition, pollinator behavior, and microbial communities, emphasizing nectar's multifaceted roles in plant fitness and ecosystem dynamics. 

Summary The black nectar produced byMelianthusflowers is thought to serve as a visual attractant to bird pollinators, but the chemical identity and synthesis of the black pigment are unknown.A combination of analytical biochemistry, transcriptomics, proteomics, and enzyme assays was used to identify the pigment that givesMelianthusnectar its black color and how it is synthesized. Visual modeling of pollinators was also used to infer a potential function of the black coloration.High concentrations of ellagic acid and iron give the nectar its dark black color, which can be recapitulated through synthetic solutions containing only ellagic acid and iron(iii). The nectar also contains a peroxidase that oxidizes gallic acid to form ellagic acid.In vitroreactions containing the nectar peroxidase, gallic acid, hydrogen peroxide, and iron(iii) fully recreate the black color of the nectar. Visual modeling indicates that the black color is highly conspicuous to avian pollinators within the context of the flower.Melianthusnectar contains a natural analog of iron‐gall ink, which humans have used since at least medieval times. This pigment is derived from an ellagic acid‐Fe complex synthesized in the nectar and is likely involved in the attraction of passerine pollinators endemic to southern Africa.