By the time Withering's masterwork was published, he was already socialising with some of the most eminent minds of his day as a member of the Lunar Society, a monthly Birmingham dining club that met on the Monday nearest the full-moon, so that its members could ride home by moonlight. As a meeting place for scientists, inventors and philosophers, the club was second only to the Royal Society and counted figures such as Josiah Wedgwood, Erasmus Darwin, James Watt, Matthew Boulton and James Priestly among its members. Like his contemporaries, Withering had many wide ranging interests and made a number of other valuable contributions to 18th Century science.
In 1776, he published A Botanical Arrangement of all the Vegetables Naturally Growing in Great Britain. The 'Botany', which was published in two volumes and illustrated by Withering's wife, was inspired by the work of Swedish botanist Linnaeus and represented the first serious attempt at a comprehensive, modern scientific study of British plant life, by classifying species according to their reproductive organs. In common with his painstaking study of the Purple Foxglove, Withering used this publication to dispel many of the claims made for the medical effects of plants and vegetables based on folklore and superstition, while it was also intended to make the subject more easily understood by readers without a classical education. The 'Botany' was an immediate success, gaining widespread acceptance throughout Europe, and for which Withering was granted fellowship of the Linnaean Society in 1789.
At University, Withering had developed an interest in Mineralogy and he was elected a Fellow of the Royal Society in 1785, for his paper Experiments and Observations on the Terra Ponderosa. As a result of his findings, Withering was credited with the discovery of Barium Carbonate, which was later renamed Witherite in his honour, by the German Mineralogist AG Werner. A rare mineral that is only found in a few locations around the world, Witherite was employed as an experimental pottery glaze by Josiah Wedgwood and has been used in sugar refining and as a preparation in rat poison!