Florae Leydensis Prodromus

Thijsse, G., Mabberley, D. J. & Baas, P., 2023, Exploring the Leiden ‘ Van Royen herbarium’: History and scientific significance of the herbarium specimens of Adriaan (1704 - 1779) and David van Royen (1727 - 1799), Blumea 68 (2), pp. 85-138 : 123-124

Florae Leydensis Prodromus

One of the manuscripts Linnaeus had brought with him when he came to The Netherlands in June 1735 was that of the Systema Naturae (Stearn 1957: 9), wherein he divided nature into three kingdoms: animals, minerals and plants. The flowering plants were grouped according to the number of stamens and pistils in the flowers. With the forthcoming enlargement of the Leiden botanical garden, Linnaeus with his new ideas of classification of all plants could not have arrived at a better time and Adriaan van Royen must have decided almost immediately to lay out the new garden according to Linnaeus’s system. The plans for the enlargement of the garden had been ready since 1730, but it would still be another ten months before these plans were implemented. In April 1736, tenders were opened for constructing the wall around the new garden. The first stone was laid on 25 June 1736. It bears the name of Adriaan van Royen’s first son Jan, who then was five months old (Brender à Brandis 1786: 10). The start of the reorganisation of the garden may also have been the reason for Adriaan to commission Laurens van der Vinne (1712–1742) to paint a flower still-life for the official residence ( Fig. 41 ).

Exactly when the enlargement of the garden was fully completed is not known. On 22 July 1738, the elder Gronovius wrote to Richardson that the garden had been expanded as far as the ramparts, but that no one was allowed access (Smith 1821: 172–173). By December 1739, the rearrangement of plants according to Linnaeus’ system had been realised and, at least by then, the work on the new garden must have been finished. 56 When Linnaeus arrived in Leiden on 9 October 1737, to say farewell, on his way back to Sweden, Adriaan van Royen was working on a new catalogue of the plants growing in the Leiden botanical garden. 57 Although Linnaeus wanted to return to Sweden as soon as possible,Adriaan managed to persuade him to stay for some time to help him organise the Leiden botanical garden according to his new system. Together they gave the plants new names and designed a new lay-out for the garden

53 Letter J.F. Gronovius (Leiden, 17 March 1739) to Linnaeus (Linnaean correspondence L0278).

54 Letter J.G. Seeger (Leiden, 20 January 1739) to Linnaeus (Linnaean correspondence L0268).

55 Letter D.S.A. Büttner (Leiden, 5 October 1748) to A. von Haller, Editions- und Forschungsplattform hallerNet,https://hallernet.org/data/letter/00764.

56 Letter J.P.Breyne (23 December 1739) to Linnaeus (Linnaean correspondence L0311).

57 Letter Linnaeus (8 October 1737) to A. von Haller (Linnaean correspondence L0216).

(Linnaeus 1826: 30–31). Linnaeus, who did not want to offend his benefactor, was reluctant to replace Boerhaave’s system with his own. Nevertheless, he felt obliged to help Adriaan and assisted him to devise a taxonomic system of his own (Linnaeus 1826: 30–31). This became the ‘Methodi naturalis praeludium’, published in Prodromus .

Linnaeus hoped that his delay in Leiden would not be too long. 58 He expected to leave in February 1738, but at the end of January he fell severely ill and had to stay in bed for six weeks. In March he was well enough to return to Clifford’s ‘Hartekamp’ to regain his strength and in May he left The Netherlands (De Gorter 1778: 127, Gistel 1873: 111, Jackson 1923: 166). 59 So, effectively his time spent in Leiden lasted less than four months. Apart from aiding Adriaan van Royen, Linnaeus was with Gronovius daily, helping him with the writing of Flora virginica (Pulteney 1805: 531) . 60 Obviously, then, Linnaeus could not have given Adriaan his undivided attention and, when he left Leiden in March 1738, there was no finished manuscript for a new garden catalogue.

On 8 January 1739 Adriaan van Royen wrote to Linnaeus that he could not find the time to devote to his beloved botany be-

58 Letter Linnaeus (8 October 1737) to A. von Haller (Linnaean correspondence L0216).

59 Letter Linnaeus (March 1738) to A. von Haller (Linnaean correspondence L0243).

60 Whether Linnaeus always stayed at one and the same address during his stay in Leiden in 1737/1738 is not clear. He himself wrote to Von Haller (Stockholm, 23 September 1739) that he stayed with Adriaan van Royen in 1738 .

cause of all his other activities. He was also pre-occupied by a very disconcerting academic feud with a person he thought of as his friend. It had caused him heartache and anxiety, making it impossible for him to even think of publishing a flora of Leiden. 61 He therefore had decided to publish what he had written so far as a precursor (i.e., Prodromus ; A. van Royen 1740 ). 62 Stoever (1794: 102) wrote that Prodromus was not the work of Adriaan van Royen , but was by Linnaeus. His source may be what he wrote to Linnaeus on 11 January 1739, namely that it was ‘tota tua est’ (= it is all yours), after he had read the Prodromus [the manuscript?] he had received from Adriaan, but perhaps he meant only that it was fully in accordance with Linnaeus’s ideas on plant classification. 63 Wijnands (1983: 28–29) wrote that there is every reason to assume that Linnaeus had contributed substantially to Prodromus , and considered it ‘as close as anything to a joint work of Adriaan van Royen and Linnaeus’. He estimated that the number of Adriaan van Royen’s specimens that may be relevant for the typification of Linnaean names could be as high as 2 000–3 000. These figures he probably based on the number of times Prodromus is cited in the first edition of Species Plantarum (c. 2 000) and the number of taxa included in Prodromus (c. 3 000).

It is almost impossible that the text for Prodromus could have been finished before Linnaeus left Leiden.Apart from giving the plants new names together (Linnaeus 1826: 30–31), it is more probable that the text was written by Adriaan van Royen himself. Linnaeus’s contribution was probably limited to formulating the new classification system. In the system Adriaan’s influence is obvious, because it is less artificial than that of Linnaeus. According to Stafleu (1971: 161) Adriaan was a major advocate of Linnaeus’s ideas, but first and foremost of his views on generic delimitation and nomenclature, not of his artificial classification system (Stafleu 1971: 161). In contradiction with this is what Linnaeus wrote (1 May 1737) to Von Haller, namely that, except for himself, nobody in The Netherlands cared about genera. Gronovius, Burman and Adriaan van Royen were only interested in herbarium specimens, although Adriaan was now beginning to look into this subject. 64 Gronovius, on the other hand, wrote at about the same time (8 February 1737) to Linnaeus that Adriaan highly praised Genera Plantarum (Linnaeus 1737b). 65

Figures

Fig. 41 Fantasy landscape with plants from the Cape. Oil painting on can- vas by Jan Laurensz. van der Vinne (1699–1753). It was commissioned by Adriaan van Royen in 1736 or 1737 and originally decorated a mantelpiece in his official residence (Museum Boerhaave, Leiden, P02657).