Unique plant specimens collected by Charles Darwin on the famous Voyage of the Beagle (1831 – 1836) are being shown in a new TV series with Susan Calman in an episode which visits Cambridge.
Channel 5’s ‘Susan Calman’s Great British Cities’ came to Cambridge and visited Cambridge University Botanic Garden (CUBG) and Cambridge University’s Herbarium (based in the Garden’s grounds) to discover why CUBG’s founder, Professor John Stevens Henslow, developed the Botanic Garden and how Henslow’s understanding of plants inspired his most famous student, Charles Darwin.
Specimens put on display for filming include a lichen specimen collected by Darwin in Tierra del Fuego in 1833 – believed not to have been looked at since Henslow’s time. It was uncovered ahead of the show with no classification or modern determination slips and has never been the subject of scientific or historical analysis.
Henslow created CUBG in 1846. His vision, was to establish a site with a major tree collection and arrange trees and plants to show their family relationships, to illustrate ideas about how plants of the same species varied. This was a theory taken up by his most famous student, Charles Darwin.
As Professor of Botany at Cambridge University, Henslow was responsible for inspiring Darwin’s love of natural history. Darwin attended Cambridge University in 1828 to study Theology with a view to becoming a parish priest but was soon skipping his own classes to attend Henslow’s botany lectures and field trips instead. Darwin took Henslow’s course three years running and by the end was assisting with teaching it.
“The extraordinary botanical collections at Cambridge University Botanic Garden and the University Herbarium, tell the story of one of the greatest teacher-student relationships in history – that of John Stevens Henslow and Charles Darwin.”
Edwin Rose, AHRC Early Career Research Fellow and Advanced Research Fellow, Darwin College, who takes part in the Channel 5 programme explains:
“A major drive for the collection of plants was to explore how they interacted with the wider world in order to gain a better understanding of ‘God’s creation’. Henslow, in particular, was fascinated with plant physiology and the question of: ‘Why does God design these plants in this way?’ Darwin was taught botany in this line known as ‘natural theology’ and there was never any doubt in God’s existence. In later life Henslow and Darwin diverged on this but that curiosity to explore plants in relation to their wider environments was sparked by Henslow’s pioneering teaching.”
Professor Sam Brockington, Curator of CUBG says: The extraordinary botanical collections at Cambridge University Botanic Garden and the University Herbarium, tell the story of one of the greatest teacher-student relationships in history – that of John Stevens Henslow and Charles Darwin. Together these two pioneers laid down a Cambridge tradition of studying plant diversity that is maintained to this day, and our botanical collections continue to drive important scientific discoveries, from the discovery of new plant species to the genetic basis of crop disease resistance.”
Henslow introduced a teaching technique fostering independent discovery. His students were given plants and asked to examine and record the characteristics of the structures they found. This method, combined with unusual field trips, interesting lectures, and Henslow’s natural enthusiasm, made botany one of the most popular subjects at the University. His class list would extend to as many as 80 students, at a time when the total University population was only in the low hundreds.
It was Henslow’s research into the nature of plant species that established the necessary intellectual framework for Darwin’s subsequent evolutionary thinking. When Darwin took his famous trip on the HMS Beagle in 1831, his place was arranged by Henslow. Darwin later described it as “by far the most important event in my life”.
Visiting the Galapagos Islands, Darwin began by arranging his observations in a framework set out by Henslow. Throughout his voyage, he was regularly posting specimens back to Henslow. Insightful letters exchanged between the two during the voyage – including Henslow complaining about Darwin’s packaging – are held at the Cambridge University Library (CUL).
During filming for the TV programme, Susan Calman visited the University’s Herbarium, in the grounds of the Garden to see some of the rare plant specimens collected by Darwin on his voyage. These included fungal herbarium specimens from Brazil that had been wrapped in the original newspaper Darwin used to preserve them on the Beagle. One news sheet shown is dated Wednesday 22 October 1828 and priced at 7d.
Two seaweed specimens, collected by Darwin on the beach of Tierra del Fuego, were also uncovered by the Herbarium team, both in incredible condition, dated 1833 with additional details recorded by their famous collector. These particular specimens correspond with letters from Darwin, held in the CUL, where he describes meeting the indigenous people of Tierra del Fuego and observing them on the beach.
Other specimens rediscovered for the filming include Opuntia (prickly pear) cacti, on which Henslow has added the name he devised for this important species “Opuntia galapagea” and where Darwin collected them – simply recorded as “Galapagos”. These were the subject of a paper by Henslow, as well as a detailed illustration also residing in the Herbarium, that he would go on to use in his teachings. The paper recorded Darwin’s observations on how the plant integrated with its surroundings and provided a vital water source for the resident iguanas. Observations of interactions between these and similar organisms proved essential in igniting the evolutionary theories Darwin published decades later.
Henslow’s progressive, hands-on teaching techniques, which included meticulous observing, collecting, storing and recording were ground-breaking for the time and are why Darwin’s detailed specimens survive to this day, informing modern research.
Dr Lauren Gardiner, Curator of the Cambridge University Herbarium says: “Plant specimens like Darwin’s, and the rest of the 1.1 million we hold at the Herbarium, are vital for modern-day research. They are verifiable evidence that allows us to monitor and see how environments have changed over time, how humans have impacted specific environments and how climate has changed environments. They allow us to extrapolate information to see if the temperature was similar in the past, or if it’s changed and using modelling we can see what the environment will be like in the future. All this evidence going backwards, allows us to predict forwards and is used in a huge amount of research these days.”
Other Darwin-related items held in the extensive Herbarium collection include: Darwin’s first ever recorded specimen, collected on a field trip with Henslow in North Wales; the diary of Darwin’s class rival, Charles Babington, who would irritate Darwin by going to the Cambridge Fens in the early mornings to collect the ‘best’ beetles first; original wall charts, illustrated by Henslow that Darwin learned from and saw displayed in the walls of the lecture room; and Henslow’s personal copies of James Edward Smith’s Compendium floræ Britannicæ (1829), in which he notes specimens found during the numerous forays to the local countryside with students–including Darwin.
Henslow remained a mentor and friend to Darwin for the rest of his life.
Susan Calman’s Great British Cities explores the relationship between Darwin and Henslow and features Cambridge University Botanic Garden and specimens from the University Herbarium as part of its Cambridge episode.
It airs on Channel 5 at 9pm on 22 March 2024 and the series is also available on My5.
