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SUMMARY: Crop–wild gene flow is common when domesticated plants and their wild relatives grow close to each other. The resultant hybrid forms appear as semi‐domesticates and were sometimes considered as missing links between crops and their wild progenitors. Wild‐growing barleys in Central and Eastern Asia, named Hordeum agriocrithon, show hallmark characters of both wild and domesticated forms. Their spikes disintegrate at maturity to disperse without human intervention, but bear lateral grains, which were favored by early farmers and are absent from other wild barleys. As an intermediate form, H. agriocrithon has been proposed several times as a progenitor of domesticated barley. Here, we used genome‐wide marker data and whole‐genome resequencing to show that all H. agriocrithon accessions of a major germplasm collection are hybrid forms that arose multiple times by admixture of diverse domesticated and wild populations. Although H. agriocrithon barleys have not played a special role in barley domestication, future analysis of the adaptative potential of bi‐directional crop–wild gene flow in extant barleys may prove a fertile research field. Significance Statement: European collection missions to Central Asia in the 1930s came across wild‐growing barleys with spikes that bear lateral grains like those of domesticated barleys but disintegrate at maturity as those of wild barley do. For almost a century, barley geneticists have repeatedly argued that those barleys, named Hordeum agriocrithon, are descendants of wild populations from which the domesticate had arisen. We used genome‐wide marker data to show that all H. agriocrithon accessions of a large genebank are crop–wild hybrids that appeared multiple times in different geographic regions by admixture of diverse wild and domesticated populations. This rules out that they are ancestral forms, but we speculate that crop–wild gene flow may have facilitated the colonization of new habitats. [ABSTRACT FROM AUTHOR]