Complex sentence: John Leonard Knapp (9 May 1767-29 April 1845) was an English botanist best known for his "Journal of a Naturalist" and his work on British grasses.
Split into simpler sentences: John Leonard Knapp (9 May 1767-29 April 1845) was an English botanist and naturalist. He is best known for his "Journal of a Naturalist", and his work on British grasses.