Dillenius, Johann Jacob

(b. Darmstadt, Germany, 1687; d. Oxford, England, 2 April 1747)

botany.

The Dillenius family were civil servants in the state of Hesse who came to Darmstadt at the close of the sixteenth century. Dillenius’ grandfather, Justus Dillenius, was a treasury clerk (Kammerschreiber), but his father trained as a doctor in the university of Giessen; after several interruptions he completed his studies and was granted a medical licentiate in 1681. Dillenius’ mother was the daughter of the clergyman Danile Funk. In 1682 the death of Laurentius Strauss left vacant the chair of medicine in Giessen and Dillenius’ father was appointed. In this academic circle the family name, which had already been changed from Dill to Dillen, was altered to Dillenius.

Johann Dillenius followed in his father’s footsteps, qualifying in medicine at Giessen in 1713. After a period of practice in Grünberg, Upper Hesse, he was appointed town doctor (Poliater) in Giessen. Mean while his passion for botany developed and led to his election to the Caesare Leopoldina-Carolina Academia Naturae Curiosorum under the name “Glaucias.” About this time he contributed several papers on cryptogams to that academy; these show his concern with the study of cryptogamic sexual organs.

Despite the promise of his work Dillenius was not offered a university post in botany in Germany. It was not until the wealthy English consul at Smyrna, William Sherard, learned of his work that he received an invitation to serve as a full-time botanist, working on Sherard”s Pinax. Dillenius accepted and by August 1721 he was in England. Apparently it was Sherard”s intention to endow the existing chair of botany at Oxford and to see that Dillenius was appointed to it. This could not be realized while Gilbert Trowe occupied the unendowed chair. Dillenius had to wait until Trowe’s death in 1734, by which time Sherard had died also. In the thirteen years which remained to him Dillenius completed his magnificent Historia muscorum (1741) and continued his study of the fungi with the help of his friend George Deering. Neither the projected book on this subject nor Sherard’s illfated Pinax was completed, however, when Dillenius died after a fit of apoplexy.

Dillenius was elected a fellow of the Royal Society in 1724 and served as its foreign secretary from 1727 to 1747. St. John’s College, Oxford, admitted him to the degree of M.D. Oxon. in 1734. His labors in Oxford marked a period of activity in botany there which was not equaled until the appointment of John Sibthorp in 1783.

Botany was passing through an exciting phase in its development in Dillenius’ student days. The sexual theory of plant reproduction had been established on the basis of experiments with flowering plants conducted by Rudolph Camerarius, but attempts to determine sexual organs in the flowerless plants had met with virtually no success. With regard to classification the state of affairs was likewise more promising for the students of flowering plants than for those who studied the cryptogams. The best work in the latter field had been that by Samuel Doody, incorporated in the second edition of John Ray’s Synopsis plantarum (1696). William Sherard was particularly concerned about the inadequate state of such knowledge, and in Dillenius he found an enthusiast for the cryptogams.

Dillenius’ failure to make headway in Germany, despite the great interest in the subject there, was undoubtedly due to his unwise criticism of the system of classification of A. Q. Bachmann (Rivinus), which was widely accepted in Germany at the time. He attacked Bachmann’s system in his Catalogus plantarum circa Gissam sponte nascentium (1719), in which the merits and demerits of the various systems of classification are enumerated with impartiality and justice. Dillenius rightly did not approve of Bachmann’s use of the regularity and number of petals as the basis for his classification and preferred the system of Ray to those of both Bachmann and Tournefort. Of course Ray’s system was not without its faults—and Dillenius did not escape a harsh reply from Bachmann. Needless to say, Dillenius failed in his role of advocate for Ray’s system in Germany.

In England, Dillenius worked on the encyclopedia (or Pinax) of all the names that had been given to each plant, on the plan originally conceived by Gaspard Bauhin. Fortunately for science, Dillenius interrupted this work frequently to undertake more fruitful tasks, the first of which was the editing of a third and last edition of Ray’s Synopsis plantarum. This work brought him into close contact with the small but active circle of British botanists who helped him with it, especially Richard Richardson.

When the Synopsis appeared in 1724 the number of flowering plant species in it had been increased to 2,200, and many new species of cryptogams had been added, including 150 moss species. This valuable work served British botanists well until the appearance of Linnaeus’ Species plantarum in 1761.

The years 1724 to 1732 were largely occupied for Dillenius with illustrating, engraving plates, and describing the plants in William Sherard’s brother’s garden at Eltham, near London. In this work no love was lost between the proud owner of the garden, James Sherard, and the ardent botanist. James Sherard, who wanted a sumptuous tribute to his glory, was greeted instead with a work of great simplicity, the chief merit of which is its very accurate descriptions and botanical illustrations of exotic plants recently introduced to Europe, especially in the genus Mesembryanthemum. Sherard never paid Dillenius for the materials needed to print the book, and Dillenius reckoned that he lost some £200 over the work.

Dillenius began putting together in Oxford the oriental plants collected by Dr. Shaw, the Oxford botanist. In 1736 he was Linnaeus’ host in Oxford, and in 1741 he published his most important book, Historia muscorum, in which he introduced a new classification of the lower plants (some features of which system are still in use to this day). In his desire to be definitive Dillenius put a prodigious amount of work into this book, which meets the high standards demanded by more modern taxonomy. But it is in the tradition of eighteenth-century British taxonomy and fails to break fresh ground in its approach to the subject or to utilize recent European advances in the knowledge of the sexual organs of cryptogams.

BIBLIOGRAPHY

I. Original Works. Dillenius’ works are Catalogus plantarum circa Gissam sponte nascentium; cum observationibus botanicis, synonymiis necessariis, tempore & locis, in quibus plantae reperiuntur. Praetmittilur praefatio et dissertatio brevis de variis plantarum methodis, ad calcem adjicitur fungorum et muscorum methodica recensio... (Frankfurt am Main, 1718); his ed. of John Ray, Synopsis methodica stirpium britannicarum... Editio tertia multis locis emendata, & quadringentis quinquaginta circiter speciebus noviter detectis aucta (London, 1724), with illustrations; Hortus Elthamensis, seu plantarium rariorum, quas in horto suo Elthami in Cantio coluit... J. Sherard... delineationes et descriptiones (London, 1732; another ed., Leiden, 1774); and Historia muscorum in qua circiter sexcentae species veteres et novae ad sua genera relatae describuntur et iconobis genuinis illustrantur: cum appendice et indice synonymorum (Oxford, 1741), of which another issue of the plates with abbreviated indices is Historia muscorum: A General History of Land and Water, etc. Mosses and Corals, Containing All the Known Species Exhibited by About 1,000 Figures, on 85 Large Royal Quarto Copper Plates... Their Names, Places of Growth, and Seasons, in English and Latin, Referring to Each Figure (London, 1768).

His correspondence with Linnaeus is included in C. Linnaeus, Epistolae ineditae C. Linnaei; addita parte commercii litterarii inediti, inprimis circa rem botanicam, J. Burmanni, N. L. Burmanni, Dillenii,... (Groningen, 1830); while Bachmann’s reply to Dillenius’ criticism of his system of classification of Rivinus is A. Q. Rivinus, Introductio generalis in rem herbarium. Editio tertia. Accedit... Responsio ad J. J. Dillenii objectiones (Leipzig, 1720).

The Dillenian herbarium is preserved at the Botany School, University of Oxford. Dillenius’ MSS are in the Sherard Collection in the Bodleian Library, Oxford. There is a portrait of Dillenius holding a drawing of Amaryllis formosissima in the Radcliffe Science Library, Oxford, and a copy of it in the Botany School, Oxford.

II. Secondary Literature. For details of Dillenius’ early life consult A. J. Schilling, “Johann Jacob Dillenius’ 1687–1747. Sein Leben und Wirken,” in R. Virchow and F. von Holzendorff, eds., Sammlungen gemeinverständlicher wissenschaftlicher Vorträge, 2nd ser., 66 (1889), 1–34.

Dillenius’ work in England is well-described in G. C. Druce, The Flora of Oxford. A Topographical and Historical Account... With Biographical Notices of the Botanists Who Have Contributed to Oxfordshire Botany During the Last Four Centuries (Oxford, 1886), pp. 381–385; and The Dillenian Herbaria. An Account of the Dillenian Collectionsin the Herbarium of the University of Oxford, Together With a Biographical Sketch of Dillenius, Selections From His Correspondence, Notes etc. (Oxford, 1907), ed. and with intro. by S. H. Vines.

For biographical information see R. Pulteney, Historical and Biographical Sketches of the Progress of Botany in England, From its Origins to the Introduction of the Linnaean System, 2 vols. (London, 1790); and A. Rees, The Cyclopaedia; or, Universal Dictionary of Arts, Sciences, and Literature (London, 1819–1820).

On his botanical work see also J. Reynolds Green, A History of Botany in the United Kingdom From the Earliest Times to the End of the Nineteenth Century (London, 1914), pp. 162–173; and M. Moebius, Geschichte der Botanik von den ersten Anfägen bis zur Gegenwart (Stuttgart, 1968), where his contributions to cryptogamic botany are discussed critically.

Robert Olby