University’s botanic garden will use study materials created by John Stevens Henslow, the naturalist’s mentor, 200 years ago

Plant specimens and teaching materials that inspired Charles Darwin and qualified him to work as a naturalist on HMS Beagle have been unearthed from an archive in Cambridge and will be used for the first time to teach contemporary students about botany.

The fragile specimens, ink drawings and watercolour illustrations of plants belonged to Darwin’s teacher and mentor, Prof John Stevens Henslow, and have been stored in Cambridge University’s herbarium for nearly 200 years.

Some of the “very rare” watercolours and drawings, published for the first time in the Guardian, are believed to be the earliest botanical illustrations Henslow produced to teach his students. Others are specimens of plants Darwin would have seen for himself.

“When Darwin came to Cambridge, he studied botany formally for the first time. He enjoyed Henslow’s course so much that he took it three years in a row,” said Dr Raphaella Hull, acting head of learning for Cambridge University Botanic Garden (CUBG). “Henslow introduced him to the concept of variation, laying the foundation for Darwin’s later theory of evolution.”