Article by Tom Barnes, The Independent
Scientists have previously struggled to determine where the plant grew, as its similarity to the related common hop meant usual methods of studying pollen fossils had proved difficult.
However, a group of researchers from the University of Vermont led by John McPartland now believe they may have solved the mystery, by examining what else was growing in the area.
In a study published in the Vegetation History and Archaeobotany, the team concluded that if other ancient pollen collected from a location were from plants common on grassy steppes, the sample is likely to be cannabis.
If other fossils suggest the area was woodland, it can be assumed the plant was a hop, the research states.
The new theory led the team to re-examine samples of Stone Age fossil pollen from more than 470 sites across Europe, concluding cannabis was present on dry tundra landscapes during the period.