In Rochester Kent, John Stevens Henslow was born in 1796. Henslow was drawn to natural history from his infancy and he had a keen interest in studying entomology and its illustration from his school days. He used to collect marine animals on family holidays for the British Museum, particularly in molluscs.
Later in 1814, Henslow attended St. John’s College, Cambridge and acquired his graduate degree in mathematics. It was this time when a significant amount of interest was developed by Henslow in mineralogy and he initiated a lifetime friendship with Adam Sedgewick – geologist. Several geological surveys were also conducted by Henslow. After graduation, Henslow supported himself by practical demonstrating in Chemistry and by teaching mathematics.
Also, Henslow was educated in Rochester and at Cambridge University. In 1821, a serious study of botany was initiated by Henslow along with Leonard Jenyns who was his young College friend. Together they both initiated a dried plant collection of the complete British flora. However, the intention of Henslow was quite different from his college friend.
The collection of Henslow was specified to the nature of species, whereas, on the other hand, Jenys was an avid and committed collector of everything in natural history. As the key to this issue, variation was studied by Henslow. For display of the variation presented between and within the population, the herbarium sheets were arranged properly by Henslow. Around 3709 sheets are present in Cambridge.
He became Professor of Mineralogy in 1822 and three years later Professor of Botany at Cambridge. He created a herbarium of British flora and later founded the Cambridge Botanic Gardens. In 1825, Professor Martyn passed away and Henslow was made the Chair of Botany. Henslow held two chairs at age 29, however, after 2 years he continued to stay as the Botany’s Professor till his death in 1861.