The ancient burial pit contained impressions from stems and flowers of aromatic plants such as mint and sage, researchers found.
The new find "is the oldest example of putting flowers and fresh plants in the grave before burying the dead," said study co-author Dani Nadel, an archaeologist at the University of Haifa in Israel.
The burial pits, the first true gravesites in the world, were excavated nearly a half a century ago from Raqefet Cave in Mount Carmel, Israel.
The region contains graves for hundreds of skeletons, including a burial of an ancient shaman woman, 'LiveScience' reported.
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Though archaeologists first excavated Raqefet Cave years ago, Nadel and his colleagues did a more thorough excavation starting in 2004.
The team found four burial sites, containing a total of 29 skeletons, which contained impressions from plant stems and flowers.
The stems had a square cross-section, a relatively uncommon trait that is found in mint, sage and other aromatic plants from the region.
The team concluded that the flowers were placed in the grave within a primitive plaster before the bodies were placed there. The bodies were buried between 13,700 and 11,700 years ago.
The study was published in the journal Proceedings of the National Academy of Sciences.