Ellis, John (c.1714–1776), naturalist, linen merchant, and administrator, was born probably in Dublin, son of John Ellis, reputedly a cutler, and Martha Ellis (née Sissons), whose father was a public notary, probably Thomas Sissons (d. 1724). Little is known of Ellis's childhood. He was apprenticed as a clothworker in London in the 1730s and remained in London for most of his life. His sisters Martha Ellis and Mary Ford (with her sons John and Roger) continued to live in Dublin. By 1733 he was established as a linen merchant in London's Lawrence Lane, trading as ‘John Ellis and James Fivey, co-partner merchants and Irish factors’. Twenty years later (1753) he was made an agent for the Irish linen board, and throughout the 1750s he lobbied parliament for the Irish linen interests. The chaotic state of the linen industry led to his firm's bankruptcy in 1760. However, his successful service to the Irish linen industry was not forgotten and he was retained as an agent by the Irish linen board, with an annual salary of £100, until his death. Friends or relatives in Dublin, including Henry Quin (qv), kept in contact with him.
Having become comfortably off in the 1740s, he began pursuing his interest in natural history. By 1744 he had amassed an interesting collection of fossils. In 1751 he received a collection of seaweeds and zoophytes (corallines) from Anglesey, and another from his sister in Dublin. He made a seascape that impressed the noted naturalist Stephen Hales, who asked him to prepare a similar seascape for the princess of Wales, with a view to helping her study natural objects. In order to arrange the items systematically, he made microscopic examinations, which convinced him that the corallines were animals. Although he was not the first naturalist to determine this – Jean Andre Peysonnel had published a treatise on the animal nature of the corallines in the Philosophical Transactions in 1751 – his researches between 1752 and 1754 laid to rest the idea that zoophytes were the intermediate links between plants and animals, and made his reputation as a marine biologist. He was elected FRS in 1754 and published his major work, Essay towards a natural history of corallines and other marine products of the like kind, commonly found on the coasts of Great Britain and Ireland, the following year (1755). This was the first comprehensive scientific study of marine vertebrates in Britain and Ireland.
In the mid 1750s he joined the Society for the Encouragement of Arts (later the Royal Society of Arts) and for the next six years served on several of the society's standing committees. In 1758 he was elected to the council of the Royal Society, and was one of the most important links between the society and the American colonies; he suggested that premiums should be offered for useful plants that could be grown in Georgia and the Carolinas. He submitted a list of ninety-four plants that might be awarded premiums and proposed that provincial research gardens be established in these areas. He worked especially to introduce tea and rhubarb to the North American colonies; he obtained rhubarb seeds from Linnaeus and sent them to Benjamin Franklin. Rhubarb, then prized as a medicine, was successfully grown.
Throughout the 1760s he continued to carry out research on zoophytes. In 1761 he examined sponges along the south coast of England with John Chandler and the Swede Daniel Solander, who later joined Sir Joseph Banks on Capt. Cook's first voyage around the world (1768–71). The following year (1762) he worked on publishing descriptions of Encrinus and Gardenia, which he named in honour of Dr Alexander Garden, a noted Florida naturalist. In 1764 he published On the nature and formation of sponges, which described sponges as animals. For his papers on Actinia sociata and the corallina, presented to the Royal Society in 1767, he was awarded the Copley medal (1768). That same year he began, at the request of Carl Linnaeus, to study fungi spores. He concluded that the spores were plant seeds and became fascinated with microbiology.
Recovering from his bankruptcy of 1760, he was appointed crown agent to Florida (1763) and Dominica (1773). He essentially controlled the funds granted by the crown to sustain the colonial government, and his primary duty was dispensing salaries to civil servants. Although he did not travel himself, he became increasingly interested in the safe transportation of seeds from the Americas and Asia to England. He proposed coating seeds with beeswax and then completely immersing them in molten wax. He published this in his Directions for bringing over seeds and plants (1770) from tropical countries. An appendix included a description of the Venus fly-trap (Dionaea muscipula), which aroused great interest. He was one of the most successful plant importers of the eighteenth century, and later wrote Coffee (1774) and Mangosteen and breadfruit (1775). After 1771 his health declined. In 1774 he moved from Gray's Inn to Hampstead, where he spent the last years of his life, dying 5 October 1776, and was buried at St Leonard's, Bromley-by-Bow.
He married (19 February 1754), in London, an heiress, Caroline Elizabeth, daughter of Sir Charles Peers (d. 1737), collector of customs and lord mayor of London (1715); they had three daughters. His wife died in 1758, shortly after giving birth to twin girls, neither of whom survived. His only surviving daughter, Martha (b. 1754), with taxonomic help from his close friend Daniel Solander and financial help from Sir Joseph Banks, posthumously published his Natural history of zoophytes (1786), which established the animal nature of coral and corallines.
Ellis was described by Linnaeus as one of the brightest stars of natural history and ‘the main support of natural history in England’ (Smith (1821), 279). His collections were placed in the British Museum, but did not survive the bombing of London during the second world war. Linnaeus named a group of boraginaceous plants Ellisia in his honour. His papers and correspondence are held at the Linnaean Society of London; they provide interesting evidence of the interconnecting networks of naturalists, colonial administrators, and merchants within which Ellis achieved prominence.