We have long wondered where cannabis really came from. All we know for sure is that it has a long history of medicinal and recreational use in various countries around the world.
Cannabis, however, is widely accepted as being indigenous to Central and/or Southeast Asia, possibly reaching Europe via ancient trading routes. In around 930 CE, Arab polymath Ibn Wahshiyya suggested that the plant came from India or perhaps China.
Now, it seems that these estimates are close enough.
Scientists had recently determined a more precise geographic origin for the plant. An analysis of fossil pollen from ancient cannabis plants points to the Tibetan Plateau as the exact place where pot first appeared.
Their findings were published in Vegetation History and Archaeobotany.
For the longest time, the exact location of the cannabis plant’s origin was hazy. This was because there wasn’t enough recorded evidence and there also wasn’t much fossil impressions of ancient cannabis to come up with specific findings.
However, scientists recently reported that there was abundant fossil pollen that represented the Cannabis genus. The only problem was that past analyses of fossil pollen in Asia had lumped Cannabis pollen together with hops and other related plants in the Humulus genus.
For the new study, the researchers separated Cannabis pollen and Humulus pollen from more than 150 studies and mapped them to regions across the Asian continent. This was done to clarify when and where Cannabis emerged.
Cannabis thrived in China
They identified fossil pollen as belonging to the Cannabis genus if it appeared alongside other pollen types from a steppe ecosystem — which is characterized by grassland and shrubland plains without trees, where cannabis is known to thrive.
The researchers discovered that the earliest Cannabis fossil pollen appeared in northwestern China. They also dated the fossil pollen back to about 19.6 million years ago.
However, the authors noted that Cannabis diverged from Humulus some 28 million years ago. This suggests that the plant might have originated somewhere else.
The researchers did not find any Cannabis fossil pollen that dates back to 28 million years ago. But they did find 28-million-year-old pollen from the Artemisia genus, which is another genus of steppe plant that grew in abundance alongside Cannabis millions of years later.
After analyses, this earliest evidence of Artemisia pointed to the Tibetan Plateau near Qinghai Lake. This location is about 10,700 feet above sea level.
The researchers used a statistical model to estimate that since the collection of plants in the Tibetan Plateau area were found with Cannabis in other locations millions of years later, it was very likely that Cannabis also thrived in this high-altitude ecosystem.
According to the researchers, from the Tibetan Plateau, Cannabis made its way to Europe around six million years ago and spread to Eastern China 1.2 million years ago.