Mary Treat was a naturalist from New Jersey who made significant contributions to the fields of entomolgy and botany. Over the period 1871–1876, she exchanged fifteen letters with Darwin - more than any other woman naturalist.

Treat initiated her and Darwin’s correspondence in 1871 at the request of their mutual friend and colleague, Asa Gray, who thought Darwin would be interested in Treat’s observations on Drosera. As her first letter shows, Treat’s interests were broad; she corresponded with Darwin on a range of botanical and entomological topics, from the relationship between the diet and sex of butterflies to the sensitivity of bladderworts.

As well as conducting research, observation and experimentations for her own publications, Treat undertook observations of plants native to America on Darwin’s behalf. In return, Darwin acted as Treat’s epistolary mentor, providing feedback on her work and advising her on where best to publish her results.

Who was Mary Treat?

Listen to Professor Tina Gianquitto (University of Mines) introducing Mary Treat, her work and her correspondence with Charles Darwin