James Petiver was a London apothecary, a fellow of the Royal Society as well as London's informal Temple Coffee House Botany Club, famous for his specimen collections in which he traded and study of botany and entomology. He corresponded with John Ray and Maria Sibylla Merian. Some of his notes and specimens were used by Carolus Linnaeus in descriptions of new species. The genus Petiveria was named in his honour by Charles Plumier. His collections were bought by Sir Hans Sloane and became a part of the Natural History Museum.
Petiver's instructions for specimen collectors, c. 1709
Musei Petiveriani centuriae, 1695
John Ray FRS was a Christian English naturalist widely regarded as one of the earliest of the English parson-naturalists. Until 1670, he wrote his name as John Wray. From then on, he used 'Ray', after "having ascertained that such had been the practice of his family before him". He published important works on botany, zoology, and natural theology. His classification of plants in his Historia Plantarum, was an important step towards modern taxonomy. Ray rejected the system of dichotomous division by which species were classified by repeated sub-division into groups according to a pre-conceived series of characteristics they have or have not, and instead classified plants according to similarities and differences that emerged from observation. He was among the first to attempt a biological definition for the concept of species, as "a group of morphologically similar organisms arising from a common ancestor". Another significant contribution to taxonomy was his division of plants into those with two seedling leaves (dicotyledons) or only one (monocotyledons), a division used in taxonomy today.
John Ray
John Ray by Roubiliac, British Museum
John Ray's birthplace in Black Notley, Essex
Blue plaque to John Ray