Sandra Diane Knapp is an American born botanist. She is currently the president of the Linnaean Society and is a merit researcher of the Plants Division of the Natural History Museum, London. While working at the Natural History Museum, London she has overseen the Flora Mesoamericana inventory of Central American plants. She has published several books on botanical subjects as well as a significant number of scientific articles. In 2016 she was awarded the Linnean Medal.
Knapp specialises in various taxa within the genus Solanum, including the Geminata clade, the Dulcamaroid clade, the Thelopodium clade, the Pteroidea group and the tomato and relatives. She is also an expert in other taxa within the nightshade family, including the genus Nicotiana and the genera Anthocercidae and Juanulloeae. Knapp has collected plants in Central and South America for the Missouri Botanical Garden and Cornell University, among others. She has also worked for the Institute for Botanical Exploration at Mississippi State University. Since 1992, Knapp has been active as a scientific researcher in the botany department of the Natural History Museum in London. She is involved in field work and research in the herbarium. She also contributes to taxonomic research of the Geminta and Dulcamaroid clades, in particular in the context of the Planetary Biodiversity Inventory project Solanum, a worldwide research project to map nightshades. She participates in a collaborative project to clarify the genomic evolution of Nicotiana. She is also active in involving the private sector in the implementation of the biodiversity treaty in Gran Chaco. She is an editor of the Flora Mesoamericana publication series, a project aimed at mapping as many plants as possible found in Mesoamerica. She has authored several books on botany or botanical exploration and has written over 200 peer reviewed scientific articles. The French-language edition of her book Potted Histories, entitled Le Voyage Botanique, was awarded the Prix Pierre-Joseph Redouté in 2004, a prize that was established in 2000 in honour of the best French-language plant book in a given year. She has also published numerous botanical names, in particular taxa within the Nightshade family. Knapp has published three botanical names of passion flowers together with lepidopteran James Mallet. One of them, Passiflora macdougaliana, they named after Passiflora specialist John MacDougal. MacDougal himself named Passiflora sandrae after Knapp.
In October 1999, Knapp discussed her book Footsteps in the Forest: Alfred Wallace in the Amazon on the BBC World Service's Science in Action. Knapp was an interviewed guest on BBC Radio 3's Night Waves in July 2013 in a segment about Alfred Russel Wallace. She appeared on the BBC Radio 4 programme In Our Time in May 2014 to explain photosynthesis. In October 2014 Knapp was a guest on BBC Radio 4's The Museum of Curiosity. Her hypothetical donation to this fictional museum was the South American freeze-dried potato product Chuño. A year later, in Natural History Heroes, a series collaborating between Radio 4 and the Natural History Museum, London she chose "Miss - not Dr - Alice Eastwood" as her hero. In July 2017, Knapp was a guest on the BBC World Service's The Forum, where she discussed Carl Linnaeus. In October 2019 Knapp appeared on In Our Time, this time to talk about hybrids.
