The book herbaria of Jacob Breyne (1637–1697) in the collection of Naturalis Biodiversity Center (Leiden

Historic herbaria can provide a wealth of information on a diversity of topics, including the past occurrence of plants, their abundance, names and uses. However, 16th and 17th century herbaria are rare and very fragile, and can best be studied after digitization. The collection of Naturalis Biodiversity Center in Leiden, the Netherlands, contains two book herbaria by Jacob Breyne (1637–1697) of Danzig (presently Gdańsk, Poland). These herbaria, dated 1659 and 1673, contain a total of 105 specimens in various states of intactness, and with or without original labels. The identity of the specimens in the Leiden Breyne herbaria was not completely assessed previously. Here we discuss the taxa represented within these two historic herbaria as well as the information contained in the handwritten texts within them. The two Breyne herbaria combined were found to contain 62 species, representing 24 plant families. Both herbaria contain several species now rare around Gdańsk, including two species currently considered regionally extinct ( Swertia perennis ( Gentianaceae ) and Dactylorhiza


INTRODUCTION
Historic herbaria are an important source of knowledge about the history of botany, and science in general. They can provide examples of pre-Linnaean nomenclature and systematics (Spalik 2014, Pulvirenti et al. 2015, Costa et al. 2018, give indications on the uses of plants in the past (Van Andel & Barth 2018) and provide evidence for the historical occurrence of species in a certain area (Santos-Guerra et al. 2011, Pulvirenti et al. 2017, Stefanaki et al. 2018. Furthermore, these collections of dried plants can provide indications about international relations and communication among scientists at the time of their production (Thijsse 2016, Offerhaus et al. 2020. They are a part of the cultural heritage of the places where the plants were collected, and as such should be made accessible to the people of these regions (Van Andel 2017). However, since they are rare and very fragile, they can best be studied using digital images.
The collection of Naturalis Biodiversity Center (NBC, Leiden, The Netherlands) contains two book herbaria made by Jacob Breyne (1637Breyne ( -1697. Breyne was born and raised in Danzig, Prussia (now Gdańsk, Poland), where his father ran a business trading raw materials for paint and medicine production, mainly Polish cochineal: a dye derived from a scale insect feeding on the roots of Scleranthus perennis L.(Caryophyllaceae) (Van Ooststroom 1942, Pękacka-Falkowska 2018, Fleischer 2019. From an early age he was interested in natural history, received lessons in botany, and took regular trips in the Danzig countryside (Fleischer 2019). Moreover, the Breyne family owned a house and garden along the river Motława, including a collection of exotic plants.
In 1653, Breyne visited the Dutch Republic, to be trained as a merchant by his uncle Pieter Breyne. While there, he visited several gardens, among which were the botanical gardens of Leiden and Amsterdam, and Lockhorst, the house and garden of Hiëronymus van Beverningk, a politician and patron of botanists such as Paul Hermann (Van Andel & Barth 2018), and he studied botany at Leiden University (Fleischer 2019). Jacob wanted to continue his studies at the Leiden medical faculty, but was called home to take on the family business after his father's death. Years later, he was offered the position of professor of Botany at Leiden University, but Breyne declined, and the position was later filled by Paul Hermann (Van Ooststroom 1942, Fleischer 2020.
Back in Danzig, Breyne continued botanizing locally, as well as corresponding with other botanists worldwide. He used his Dutch connections to contact people working for the Dutch East India Company (Vereenigde Oostindische Compagnie, VOC), and thus gain access to plants, seeds, bulbs and dried specimens from Asia and the Cape of Good Hope (Gunn & Codd 1981, Pękacka-Falkowska 2018, Fleischer 2019. The book herbaria of Jacob Breyne (1637Breyne ( -1697 in the collection of Naturalis Biodiversity Center (Leiden, the Netherlands) M. de Jong 1, *, H. Duistermaat 2 , A. Stefanaki 2,3 , T.R. van Andel 2,3,4 Breyne published two major works on (mainly exotic) plants: Exoticarum aliarumque minus cognitarum plantarum centuria prima (Breyne 1674(Breyne -1678; known for short as the Centuria) and Prodromus fasciculi rariorum plantarum I & II (Breyne 1680(Breyne -1689Prodromus), which he printed himself. He planned on publishing works on local plants, entitled Pomerelliae Viridarius and Viridario Borussiaco (Pękacka-Falkowska 2018, 2021, but never finished them. His manuscripts on Prussian plants were later used by Gottfried Reyger, who wrote his Tentamen Florae Gedanensis Methodo Sexuali Accomodatae (Reyger 1764) on the flora of the area around Danzig (Pękacka-Falkowska 2018). Jacob Breyne is remembered in botany today for several things: he was one of the first Europeans to describe the tea plant (Camellia sinensis (L.) Kuntze, Theaceae), based on a description (and possibly dried plant parts) sent to him by Willem ten Rhyne (1649 -1700) from Dejima, Japan (Gunn & Codd 1981, Fleisher 2020. He also coined the name Mesembrianthemum for a genus of plants in the Aizoaceae, originating from the South African Cape region. According to Gray (1880), Linnaeus adopted this name in his Species Plantarum (Linnaeus 1753), but misspelt it as Mesembryanthemum, which has become the official spelling. Finally, the genus Breynia J.Forst. & G.Forst. in the Phyllanthaceae was named after Breyne by Johann & George Forster (Forster 1776). Linnaeus also named a genus after Breyne (also called Breynia (Linnaeus 1753) ), but this has been synonymized with Morisonia Plum. ex L. (Capparaceae).
The two Breyne herbaria at NBC contain a source of information which is, as of yet, largely unexploited. It can show developments in plant nomenclature, both on a longer and shorter time span. The labels written by Breyne contain one or several names by pre-Linnaean authors, such as Johann and Caspar Bauhin, Conrad Gessner and Mathias de l'Obel, as well as some local vernacular names. Then there are the labels added to the 1659 herbarium by De Monchy, of the Rijksherbarium in Leiden (now part of NBC), in the early 20th century, and the article on the 1659 herbarium by Van Ooststroom (1942). These contain binomials in the Linnaean system. Furthermore, from Breyne's descriptions, we can trace the locations where he collected his specimens, and then see whether these species still occur there. The landscape around Gdańsk is bound to have changed over the three-and-a-half centuries since Breyne collected his plants, due to the expansion of the city and other changes in land use and climate. Hence, plants which may have been common in Breyne's days may now be very rare, or vice versa.
Breyne's notes in the herbaria could also give some indications of how the plants he collected were used in his day. Living in an era before artificially synthesized medicine, and a trader in the raw materials for dyes and medicines himself, Breyne is likely to have been interested in the practical uses of plants.
Finally, these herbaria are part of the cultural heritage of the area in which the plants were mostly collected (Pomerania province, northern Poland), but they have been stored away in the NBC 'Rare Book Room', not accessible to the public. This research will open up this piece of Polish heritage, by adding the plants' details and digital images of the herbarium to the online Naturalis Bioportal (bioportal.naturalis.nl), where they can be easily and freely accessed.
While exploring the Breyne herbaria and their importance to science today, we wanted to answer the following questions: -Which species are included in the two Breyne herbaria? To which extent do these represent European / Polish (Prussian) or exotic plants? -Did Breyne use a particular arrangement in his herbaria (by family/resemblance, by location, alphabetically)?
-Do the accompanying descriptions and labels give indications of the plant uses, collecting locations and abundance, and do these species still occur around the same locations? -To which extent are the represented species discussed in Breyne's Centuria and Gottfried Reyger's Tentamen?

METHODS AND MATERIALS
Both Breyne herbaria in the NBC collection have been digitized, and high-resolution images were used for the identification of plant specimens. These images are freely available through the Naturalis Bioportal, and can be found by typing the associated barcode into the search field. When identification depended on details not visible on these images (e.g., hairs, small floral parts), then the herbarium specimens were physically examined under a stereo microscope. To analyse the names, locations and uses stated by Breyne, transcriptions of the labels by Pękacka-Falkowska (2018) and Van Ooststroom (1942) were used.
The identification of plants from the Breyne herbaria was conducted using floras covering eastern Europe (Tutin et al. 1964, Mirek et al. 2002, Jäger 2011, Seybold 2011, as well as the Netherlands (Duistermaat 2020). The names provided by the identifications of De Monchy and Van Ooststroom were checked against the aforementioned works, and in the International Plant Names Index (IPNI continuously updated) and Plants Of the World Online (POWO continuously updated). These sources were also used to find older synonyms of current names to aid searching for these taxa in other sources.
The current occurrence of taxa was checked using a checklist for the Polish flora (Mirek et al. 2002). The current conservation status was assessed using the red list for Gdańsk and the surrounding area (Markowski & Buliñski 2004).
Digital versions of Breyne's Centuria (Breyne 1674(Breyne -1678 and Prodromus (Breyne 1680(Breyne -1689) and Reyger's Tentamen (Reyger 1764) were used. The presence of plants in these works was checked by searching for the pre-Linnaean names used by Breyne, and comparing descriptions with these names to the specimens in the herbaria.
The paper sheets used to construct the herbaria were checked for watermarks, in order to reconstruct the origins of the paper via the online Memory of Paper database (www.memoryofpaper.eu). The two herbaria combined contain a total of 105 plant specimens, although many more were originally present, judging from the remains of plants, labels and pages. The 1659 herbarium consists of two bundles of loose, thick paper sheets, folded over to produce a book-like structure. It lacks a cover of its It is yet unknown which paper producer is associated with this mark.

Fig. 2
A specimen of Helichrysum arenarium from the 1673 herbarium. This species is represented by six specimens in this herbarium.
own, but has been wrapped in an early 20th century cover with the Dutch title Herbarium door JACOB BREYNE verzameld in de omgeving van Danzig. Anno 1659 (Herbarium by Jacob Breyne, collected in the surroundings of Danzig. Anno 1659). It contains 48 specimens, one or several per page, although a large number of empty sheets with remains and imprints of plants suggests there were once more. The second last sheet of the herbarium contains a watermark in the shape of an elephant with a 'B' on its body (Fig. 1). This watermark is not represented in the 'Memory of Paper' database. Hence, the origin of the paper is yet unknown.
The 1673 herbarium is bound into a book with the title Plantae Rariores Borussiacae et Cassubicae anno 1673 (Rare Plants of Prussia and Kashubia anno 1673). It contains 57 specimens, generally one per page, and seems to be missing fewer plants than the 1659 herbarium: at least ten plants seem to be missing, and twelve pages have been cut out. Breyne is known to have made a 'duplicate' of the 1673 Leiden herbarium, which he sent to James Petiver in England and which is now in the collection of the Natural History Museum in London (as part of the Sloane Herbarium, HS 231, ff. 88-113), but not yet digitally available (Britten et al. 1958, Fleisher 2020. Future research into this herbarium could possibly give more insights into the specimens lost from the Leiden herbaria, but is beyond the scope of the current paper. A recent paper by Pękacka-Falkowska (2021) sheds more light on the correspondence between Breyne and Petiver.

Specimen composition
Both herbaria contain a large diversity of plants. A complete list of taxa present can be found in Appendix 1 for the 1659 herbarium and in Appendix 2 for the 1673 herbarium. The combined total of 105 specimens in both herbaria consists of 62 species from 24 families, including two Lycopodiaceae species and one fungus. Well-represented families are Asteraceae (29 specimens, 13 spp.) and Apiaceae (9 specimens, 5 spp.); 11 species were found in both herbaria. The same number of species were represented more than once within one of the herbaria (6 spp. in the 1659 herbarium, 5 spp. in the 1673), with six specimens of Helichrysum arenarium (L.) Moench (Asteraceae) (Fig. 2)

Removal of specimens
From the 1659 herbarium at least 60 specimens have been completely removed, as indicated by the remains of plants, labels and glue ( Fig. 3). At least ten plants were removed from the 1673 herbarium. The removal seems to have taken place before the 20th century: Van Ooststroom (1942) mentioned only the plants currently present, and also, evidence is lacking that De Monchy has identified plants that are no longer present. This means that any of the owners between Breyne himself and, eventually, the Rijksherbarium, could have removed (part of) the missing specimens.
Some plants have left impressions in the paper, giving indications of their shape and size. Determining species just from this imprint was, however, impossible. Where a plant had been removed, but labels and/or written text on the sheet remained, a tentative identification was attempted, such as in a case where Breyne mentioned 'nidus avis', and described a plant with stem, flowers, leaves and roots in a single, pale colour. The name, together with the mentioned colour pattern indicate that a specimen of the Bird's-Nest Orchid (Neottia nidus-avis (L.) Rich., Orchidaceae) was once present here. The same has been done for other pages with missing plants. Names deriving from these tentative identifications have been put between brackets in Appendices 1 and 2.
In a few instances, only the label was removed, often very roughly, while the corresponding specimen is still in place. This indicates a certain specific interest in the labels, as well as the specimens. It is unclear why someone removed these labels from the herbarium rather than simply copying the information.
On several pages, plant names have been written, but there is no indication that plants and/or labels were once present on these same pages. Fifteen such situations are found in the 1659 herbarium. Although plants may have been removed from these pages, leaving no traces, it is more likely that these pages never contained any plants, and that these names were just notes by Breyne, indicating species he was planning to include in the herbaria. From the 1673 herbarium, twelve pages have been cut out. These may or may not have contained plants. Again, it is not known who cut out these pages and why.
Both herbaria seem to have had their pages ordered differently in the past, as indicated by the page numbers written in the top right corner. The original numbers in the 1673 herbarium have been crossed out, and new numbers were written underneath. Why the order of the pages was changed, and who changed the page numbers in the 1673 herbarium, is as yet unknown.

Order of specimens
The plants within the 1659 herbarium do not seem to follow any particular order with regards to family, habitat, alphabetic or otherwise. Within the four sections of the 1673 herbarium, however, plants are arranged according to family, although Breyne most likely did not use the system of plant families as we know it today, but arranged his plants according to their resemblance, either observed by himself or by previous authors (Table 1).
An exception is a mixing-up of Cyperaceae and Juncaceae in section 2. Breyne used the name 'Gramen' (grass) for most of these species (2 Cyperaceae, 2 Juncaceae and 2 Poaceae; for one Cyperaceae species, Breyne uses 'Juncus' (rush)), indicating that he considered them to be of the same group.

Fig. 5
Two leaves and an inflorescence of Laportea canadensis (above) and a specimen of Lycopodium sp. (below). Laportea canadensis is not known to occur in Europe, and so may have been sent to Breyne from its natural range in North America, or from a plant in cultivation.

Exotics
Breyne's herbaria contain 34 species not known to (currently) occur in the region around Gdańsk (see Appendix 3). These may have been collected on trips further afield, or sent to Breyne by one of his many correspondents. One such exotic is a specimen of Laportea canadensis (L.) Wedd. (Urticaceae) in the 1659 herbarium (Fig. 5). This plant is native to the eastern parts of North America, and not known to have been introduced or escaped into the wild in Europe (Chew 1969). Judging from the small size of the specimen (two single leaves and a small inflorescence, rather than an entire plant), it may have been sent to Breyne in a letter, either from North America, or from a plant in cultivation. Sadly, Breyne did not label this specimen, leaving us to guess at its origins.
Other plants not currently known from the Gdańsk region include several species more commonly associated with higher elevations, such as Buphthalmum salicifolium L. (Asteraceae). Although the Gdańsk region is at a comparatively low elevation, Breyne mentions many of his collecting sites as being located between heather on hilly grounds, where some of these highelevation species may have found a home too.

Ecological notes
On the labels of many specimens in the 1659 herbarium, Breyne provides notes on the collecting location. These notes often include the name of a town, but also some ecological remarks, the detail of which is remarkable for an early herbarium such as this. Many plants have been collected 'inter ericas', i.e., between heather. Some plants were collected in woodlands or meadows, many in hilly or mountainous surroundings. One specimen was collected 'in a lush forest', a second 'in a dark forest', while another was collected 'in a valley, at the side of running fountains'. According to his labels, Breyne collected multiple specimens in the grasslands around the Danzig gallows. The ecological notes in Breyne's herbaria can give us clues on the historical occurrence of ecosystems at the associated collecting locations. They show the occurrence of (possibly quite extensive) heather-covered hills in the Gdańsk area, as well as peatland ecosystems at 'Insula Neringa' (Mierzeja Wiślana), judging from specimens of Eriophorum vaginatum L. (Cyperaceae) and Vaccinium uliginosum L. (Ericaceae) collected there.
In one particular case, Breyne mentions on his label the cooccurrence of another species. For a specimen of Pyrola chlorantha Sw. (Ericaceae), Breyne mentions it growing where 'Calceolus Mar.' also grows. This name could refer to Calceolus marianus Mill., now a synonym of Cypripedium calceolus L., the Lady's Slipper Orchid (Orchidaceae).
On the labels of many specimens, Breyne mentions the flowering time. The months May, June, July and August are mentioned, suggesting Breyne collected mainly in these months. Other remarks found on the labels of both herbaria can be found in Appendix 4.

Collecting locations
On many labels in the 1659 herbarium, the location of collecting is mentioned (no place names are mentioned in the 1673 herbarium, except for Kashubia and Austria). Breyne used the German names of Prussian towns, and often with a deviating spelling. Many places are in the direct surroundings of Danzig, such as Bahrenwinkel (now Niedźwiednik), Jasken / Jaskendahle (Jaśkową Doliną), Bringenz (Brȩtowo) and Miggauw (Piecki-Migowo) (Fig. 6). Another popular collecting location was near the monastery at Oliwe (Oliwa). Two locations are further from Danzig: Beren / Beeren (Kościerzyna) and Neeringh / Insula Neringa (Mierzeja Wiślana). One town in central Poland is mentioned (Torunia; now known as Torún), from which Breyne was sent a specimen of Pulsatilla Mill. (Ranunculaceae).

Uses
With four specimens in the 1659 herbarium, Breyne mentioned that the plants were used by people. For two specimens of Rhododendron tomentosum Harmaja (Ericaceae) (pages 6 and 27), the use of this plant in brewing beer was mentioned. Breyne notes that the Swedes had imported 20 'voeder' (cartloads)   (Riddle 1997). This indicates the application of H. selago as an abortifacient drug; a use indeed known from other parts of Europe (Hatfield 2004, Kenicer 2018).
Breyne also mentioned the consumption of the berries of Vaccinium uliginosum L. (Ericaceae) (a specimen on page 5), and how eating a large amount can cause drunkenness, "as if one had drunk much wine". The berries of this species are still eaten, and are known in German as Trunkelbeere ('drunk-berries') (Jäger 2011 Breyne mentioned that the plants were harvested in the mountains only, and that they were given in bundles to young ladies in the spring, because of their scent. Anthoxanthum nitens is known for its scent, and was used as a strewing herb. As such, it was commonly used in churches, and even used as an alternative to incense (POWO continuously updated). In this context, it was dedicated to Mary in the Christian religion, which explains Breyne's use of the name Gramen Mariae.

Previous owners of the herbaria
Both herbaria seem to have been sent to correspondents of Breyne. It is known that both herbaria were in the possession of Hiëronymus van Beverningk (Pękacka-Falkowska 2018), but it is unknown whether he was the original receiver, or that he acquired them later. In a piece of text written on an unnumbered sheet, Breyne states he has received 'Pulsatilla caerulea odoratissima' from Jacobus Hase, from Thorunia (Torún). It is unknown who Jacobus Hase was, and how he related to Breyne.

Centuria, Prodromus and Tentamen
Out of all species represented by specimens in both herbaria, only one is mentioned in Breyne's Centuria (1674: 130). This concerns what is probably a double-flowered form of water avens (Geum rivale L., Rosaceae). The Centuria contains an image of this plant, showing its multi-petalled flowers. None of the species present in the herbaria were mentioned in the Prodromus. Of the species in the 1659 herbarium, 12 are mentioned with a matching name and description in Gottfried Reyger's Tentamen (1764), while three species match partially (i.e., a very similar name with a matching description). For the 1673 herbarium, nine species match in name and description, while seven do so partially (Appendix 5). With seven specimens, Breyne mentioned his planned works Pomerellia Viridario and Viridario Borussiaco, which he never finished. Possibly, Breyne had already decided to include these species in his manuscripts, and used these specimens as a basis for his illustrations and/ or descriptions.

Origin of specimens and function of the 1659 herbarium
Although most specimens in the 1659 herbarium have indications of their collecting location, and were thus most likely collected by Breyne himself, there are indications that some plants were sent to Breyne by others. In Breyne's days, a network of scholars exchanged knowledge (and for botanists: plant specimens) through letters. This network was known as the Republic of Letters, and included intellectuals from all over the world (Daston 1991). Breyne corresponded with many fellow botanists in Europe and elsewhere, such as Willem ten Rhyne (a doctor in service of the Dutch East India Company (VOC), visiting Japan and South Africa) and Hiëronymus van Beverningk in Leiden. Moreover, Breyne may have corresponded with garden owners and nurserymen, exchanging knowledge as well as specimens.
For some of the specimens in the 1659 herbarium we may expect that they came to Breyne through letters. Firstly, with two specimens Breyne actually mentioned the plants being sent to him. The specimen of Swertia perennis L. (Gentianaceae) on page 2 was sent by 'UE' ('Your Honour', see above). In a piece of text without a plant on an unnumbered sheet, it is mentioned that a specimen under the name of 'Pulsatilla caerulea odoratissima' was sent from Thorunia (Torún) by Jacobus Hase.
(Urticaceae) on page 13 may have been sent to Breyne as well, from North America or from a plant in cultivation. This species is not known to occur naturally in Europe, so it is unlikely that Breyne would have encountered it on his countryside trips. Secondly, the small size of the specimens would have allowed them to be included with a letter. Sadly, the Laportea specimens were not labelled by Breyne, leaving us without further clues as to their origin.
Although some references to a receiver ('UE', see above) would indicate that the 1659 herbarium was meant as a gift, the large number of pages without indications of plants being present would suggest a different use of (part of) this herbarium. Perhaps, Breyne used these sheets to (temporarily) store plants he received from, or was going to send to others, or that he was planning to discuss with fellow botanists. The 1673 herbarium was most likely made as a gift, judging from the large and elaborately arranged specimens, the amounts of text on each label and the fact this herbarium has been bound into a hardcover, as opposed to the loose sheets of the 1659 herbarium.

CONCLUSIONS
The two Breyne herbaria in the Leiden collection contain 62 species from 24 families, represented by a total of 105 specimens. While the specimens do not seem to have been placed in any particular order in the 1659 herbarium, a family-like arrangement is found in the 1673 herbarium. Many taxa are native to eastern Europe; the 34 represented taxa not locally native may have been sent to Breyne through his contacts in the Republic of Letters or collected on trips further afield. All of Breyne's collecting locations were reconstructed using his writing on the labels, yielding locations mostly near Gdańsk.
Many taxa are rarer today than they were in Breyne's day, as indicated in his handwritten texts on the labels. Out of all taxa in both herbaria, 24 are represented on a Red List for Gdańsk and surroundings and two in the Polish Red List. The species Swertia perennis and Dactylorhiza viridis are now considered regionally extinct, even though D. viridis was mentioned by Breyne as 'flowering in great abundance'. This shows the importance of historical herbaria in the reconstruction of the past distribution of plants, and the changes in the landscape around Gdańsk over the past three centuries.
Breyne mentioned uses of four taxa, as a strewing herb, for brewing and consumption, and as an abortifacient drug. Only one taxon represented in the herbaria is also mentioned in Breyne's 1674 Centuria (Geum rivale); none are mentioned in the Prodromus. Reyger (1764) mentioned multiple taxa found in Breyne's herbaria in his Tentamen.
The Breyne book herbaria give us an insight into the state of botany in the second half of the 17th century. After identification of the specimens, the names as given by Breyne, which he cited from the works of many other botanical authors, can be attributed to a modern binomial. Both herbaria, but especially the 1659 herbarium with its references to collecting locations, contain evidence for the historical occurrence of plant species, informing us on land use change, and allowing for informed decisions in the possible reintroduction of species.
As biodiversity worldwide faces large threats, it is important to know what species were once there, and their former abundance. This can help us understand what is already lost, and what we need to protect, or possibly restore. Herbaria in general have an important role to play in this process, but historical herbaria even more so. They can provide evidence of the occurrence of plants in pre-industrial times, showing parts of the vegetation of the area in which they were collected, before modern human interference. In addition, historical herbaria can provide information on the connections between plants and humans, in times when this was much more important in everyday life, than it is (or, rather, seems to be) today. Further research into the contents and producers of historical herbaria may help us in our aims to preserve biodiversity, as well as provide insights into the history of science and society in general.      (Mirek et al. 2002). Tentative identifications are listed in brackets. (y = yes, n = no).
Appendix 3 Current occurrence of species from the herbaria in Pomerania *.