Paul Hermann, medical practitioner and botanist, started collecting plants as a child and at the age of ten nearly drowned in the process. He studied medicine at Wittenberg, Leipzig and Padua, Italy, where he took his degree in 1670. After a tour of Italy he moved to the Netherlands, where he became known among botanists. In 1671, on the recommendation of Professor A. Seyen of Leiden and an influential official and plant cultivator, W. Bentinck, he was appointed by the Dutch East India Company as chief medical officer of Ceylon, and given the additional task of collecting plants in India, Africa and Ceylon. On his way to Ceylon he became the first competent botanist to visit the Cape, in April 1672. On the return journey he again touched at the Cape in March 1680. During his short stay he collected more plants in the vicinity of Cape Town than everyone before him combined. One of his specimens is now the earliest preserved alga to be collected at the Cape, a specimen of Amphiroa too damaged to determine the species. He formed a herbarium of his specimens and sent seeds and bulbs to the Netherlands to be cultivated. He also gave some specimens and seeds to a ship's surgeon, Hieremias Stolle; these were described by Thomas Bartholinus of Copenhagen in a short note, "Plantae novae Africanae" in his Acta Medica et Philosophica Hafniensia (1675) - the first paper devoted entirely to Cape plants.
While residing in Colombo, Ceylon, Hermann collected an impressive herbarium, mainly in the coastal region around Colombo, and developed a unique knowledge of the Ceylon flora. His specimens were bound in four volumes, of which the fourth included his Cape plants. The famous botanist C. Linnaeus later based his Flora Zeylanica (1747) on this herbarium. Hermann regularly sent seeds, roots and bulbs to Seyen and Bentinck, most of which ended up in the botanic gardens of the University of Leiden. Collections were also sent to other prominent persons. At some stage, probably in 1674, he visited Malabar (the coastal region of south-west India) where he seems to have advised H.A. van Reede* on the scheme of his Hortus Malabaricus. Having become well known in Europe for his botanical work, he was offered the chair of medicine and botany, including the directorship of the botanic gardens, at the University of Leiden in November 1678, following the death of Professor Seyen. His letter of acceptance is dated 23 October 1679, the mail being rather slow in those days. Returning to the Netherlands he assumed duty in August 1680.
Hermann's duties included lecturing on botany, which he did in the university's botanic gardens. In his lectures he gave much attention to taxonomy, being the first Dutch teacher of botany to do so. He visited England in 1682, especially the botanic gardens at Oxford University and Chelsea, and brought back almost 200 living plants. During holidays he also visited Germany and France. In 1683 he became secretary of the university senate. From 1686 he also had to teach practical medicine, for which he was paid extra. During these years he was responsible for reorganising and greatly expanding the university's botanic gardens, adding glass houses to cultivate plants from warmer climates and introducing many new species, including rare plants from all over the world. Thus the gardens became an important centre of colonial botany in Europe. In April 1685 the curators of the gardens ordered a catalogue to be compiled of the plants cultivated there. Hermann produced a large, illustrated catalogue of some 700 pages, Horti academici Lugduno-Batavi catalogus..., which was published in Leiden in 1687. It listed some 3000 plants, including many from the East Indies and Virginia (now part of the United States). Also included were 34 Cape plants, several of which were described and illustrated for the first time: twelve Mesembryanthema (vygies), ten species of Pelargonium, two lilies, Stapelia variegata, some Crassula, and a number of shrubs. In 1690 he published Florae Lugduno-Batavae flores..., a catalogue of the plants used in his practical teaching.
A keen observer and industrious collector, Hermann was indisputably the greatest Dutch botanist of his time and one of the greatest of senventeenth century Europe. He died at the relatively young age of 49, leaving his wife, Anna, née Stomphius, and four children.
Hermann's study of exotic plants growing in Dutch gardens, in collaboration with his English pupil William Sherard (1659-1728), led in 1689 to a preliminary list of plant names, Pauli Hermani Paradisi Batavi Prodromus, edited by Sherard. At the time of his death Hermann had almost completed an illustrated volume of these plants, most of them from the East and West Indies and the Cape. It was finally prepared for publication under the title Paradisus Batavus... by Sherard in 1698, with another edition following in 1705. The catalogue of Hermann's Ceylon herbarium, probably edited by Sherard, was published anonymously in 1717 as Musaeum Zeylanicum. An inventory of his Cape plants, listing 791 specimens, was published as an appendix to Johannes Burman's Thesaurus Zeylanicus... (1737). His extensive collections were split up, but most of the material was eventually incorporated in the Sloane Herbarium and other collections of the British Museum (Natural History). Other specimens are in the herbarium of the Department of Botany, Oxford University. He was commemorated in the genus Hermannia by Linnaeus.