Two new bamboo varieties have been discovered through fossil study. Found in Assam, they are said to be among the oldest fossils of Asian bamboo to be found so far—about 25 million years ago in the late Oligocene period, according to researchers.
With more than 49,000 plant species (as of 2018), India has about 11.5 per cent of all flora in the world.
Studies by an international team of researchers have found two fossil compressions or impressions of bamboo culms (stems), which have been named Bambusiculmus tirapensis and B. makumensis, as they were found in the Tirap mine of the Makum Coalfield in Assam. They also have two impressions of bamboo leaves belonging to new species Bambusium deomarense, and B. arunachalense, named after the Doimara region of Arunachal Pradesh where they were found. These leaves have been assigned to the late Miocene to Pliocene sediments.
A paper relating to this was published recently in the journal, Review of Palaeobotany and Palynology.
Though the province of Yunnan in China now has the most diversity in bamboo plants, the oldest fossil in that region has been dated to less than 20 million years there.
Bamboo today is a plant that can grow in varying climates—from as cold as 5 degree C to a very warm 30 degrees C, and even at sea level to heights of about 4,000 metres. They can survive in varying rainfall conditions too.
The dominant theory is that bamboo came to Asia from Europe. The European bamboo fossil is said to be about 50 million years old. But the researchers involved in the study state that though the Indian plate collided with the Eurasian plate about 50 million years ago, the suturing between the two plates were not completed until 23 million years, i.e., the plates were not completely joined. So there was little migration of plants and animals before that. Hence, they claim that that the plants indicated by the new bamboo fossils could have not arrived from Europe.
At that time, the temperature was warm and humid in the north-eastern region, with not many seasonal variations. The present climate in the region is cold with strong winter and summer conditions. Bamboo withstood the climatic and geographical changes.
Bamboo fossils are rare in India and they have been known to be only in the Siwalik sediments. Paleobotany, too, as such is not studied widely in the country.