Birbal Sahni, FRS (1891-1949) was an Indian paleobotanist who studied the fossils of the Indian subcontinent. He founded what is today the Birbal Sahni Botanical Institute in Lucknow, India. Birbal Sahni was born on 14th November 1891 and got his early education in India at Lahore and graduated from Emmanuel College, Cambridge in 1914. He later studied under Professor A. C. Seward, and was awarded the D.Sc. degree of London University in 1919. He returned to India and served as Professor of Botany at Banaras Hindu University, Varanasi and Punjab University for about a year. In 1921, he was appointed as the first Professor and Head of the Botany Department of the Lucknow University. The University of Cambridge recognized his researches by the award of the degree of Sc. D. in 1929. During the following years he not only continued his investigations but collected around him a group of devoted students from all parts of the country and built up a reputation for the University which soon became the first Center for botanical and palaeobotanical investigations in India. He established the Institute of Palaeobotany under the aegis of The Palaeobotanical Society on 10th September, 1946 which initially functioned in the Botany Department of Lucknow University but later moved to its present premises at 53 University Road, Lucknow in 1949. On 3rd April, 1949 the Prime Minister of India Jawaharlal Nehru laid down the foundation stone of the new building of the Institute, however, a week later, on 10th April 1949, Professor Sahni succumbed to a heart attack. Professor Sahni was recognized by several academies and institutions in India and abroad for his research. He was elected a Fellow of the Royal Society of London (FRS) in 1936, the highest British scientific honor, awarded for the first time to an Indian botanist.
His greatest contribution was the discovery of a new group of fossil gymnosperms which he called the "Pentoxyleae". Sahni studied fossil leaves of Ptilophyllum, stem of Bucklandia and flower of Williamsonia and concluded that they all belong to the same plant which he reconstructed and named as Williamsonia sewardiana. He was elected Vice-President, Palaeobotany section, of 5th and 6th International Botanical Congress 1930 and 1935, respectively; General President of the Indian Science Congress for 1940; President, National Academy of Sciences, India, 1937-1939 and 1943-1944. In 1948 he was elected a foreign Honorary Member of the American Academy of Arts and Sciences. Another high honor came to him was his election as an Honorary President of the International Botanical Congress, Stockholm in 1950.