Many herbarium sets in Europe are still being catalogued and it is likely that many old-type collections are yet to be discovered. This research has the potential to facilitate the study of the biodiversity of many regions, especially regions for which collections are extremely scarce. This has been confirmed by a case study using Juncus (Juncaceae) examining the turbulent history of botanical collections at the WRSL herbarium and the evaluation of its importance to the study of taxonomy and biodiversity since 1821. The analysis revealed that the WRSL collection is rich in types (ca. 3.6%) and we identified 76 (of 78) new, historically and nomenclaturally important specimens (types, original material and so-called “topotypes”). Some of these type specimens represent duplicates of these that were stored in Berlin and destroyed during World War II. Many of the type specimens are from the United States of America, South Africa, India, and Canada. The largest number of Juncus type specimens stored at WRSL originate from South Africa (42.3% of all type specimens), even though Juncus is rare in Africa. Our study highlights that uncatalogued old collections that are under-explored and under-exploited have the potential to facilitate the discovery of specimens important for the study of biodiversity, conservation, taxonomy and nomenclature.

biodiversity, conservation, historical collections, Juncaceae, Juncus, plant taxonomy

The Natural History Museum of Wrocław University (Muzeum Przyrodnicze Uniwersytetu Wrocławskiego) is the oldest natural history museum in Poland and its history dates back to 1814, when it was founded by Prof. Johann Ludwig Christian Gravenhorst as the Zoological Museum. Currently, it houses both the botanical and zoological collections. The beginning of the herbarium in its present form was the Herbarium Horti Botanici Universitatis Wratislaviensis, which was established by Prof. Ludolph Christian Treviranus in 1821 (Wiktor 2002; Wanat 2013). The Herbarium Silesiacum was independently founded by the Silesian Association of Native Culture (Schlesische Gesellschaft für Vaterländische Cultur) and, until 1945, it was housed on Tamka Island, Wrocław. It developed independently from the other botanical collections, but following the Second World War, it was merged with the main part of the herbarium.

Many distinguished botanists have worked in the WRSL herbarium (Museum of Natural History, University of Wrocław, Poland, in Polish: Zielnik WRSL), including the directors or curators of Wrocław’s botany collections, for example, Ludolf Christian Treviranus (1821–1830), Christian Gottfried Nees von Esenbeck (1830–1852), Heinrich Robert Goeppert (1852–1884), Heinrich Gustav Adolf Engler (1884–1889), Ferdinand Cohn (1884–1893) and Ferdinand Pax sen. (1893–1927). The Herbarium Silesiacum was curated by Julius Milde (1865–1870), Gustav Wilhelm Körber (1871–1885), Rudolf von Uechtritz (1886), Theodor Schube (1890–1929) and Emil Schalow (1930–1944) (Wiktor 2002).

Professor H.R. Goeppert expanded the botany collections and established the Botanical Museum (Botanisches Museum) in 1853 (Wanat 2013). The first known catalogue of the Museum (Goeppert 1884) included 26 different collections, including the Herbarium of the World, the Herbarium Silesiacum, the Herbarium Mycologicum, a wood collection and several fruit and seed sets. Goeppert also opened another museum in 1878 – The Museum of the Botanical Garden (Mularczyk 1998). In 1888, all these several botanical collections belonging to the University were moved to a building that is today located at 6/8 Kanonia Street. However, they still consisted of two separate collections (the Botanical Museum in charge of Prof. Cohn and collections of the Herbarium and the Museum of the Botanical Garden in charge of Prof. Engler). Due to the efforts of Prof. Engler, a private Silesian plant collection assembled by Rudolf von Uechtritz was purchased at this time and M. Winkler donated his herbarium to the Museum, which he had compiled for 30 years (Wiktor 2002).

At the end of nineteenth century, Ferdinand Pax (the elder) merged all the University botanical collections under the name of the Botanical Museum. His own collections were also included in the Museum at this time. Before merging, von Uechtritz’s herbarium of Silesian plants was handed over to the Herbarium Silesiacum (then still independent) on his initiative. In exchange for Uechtritz’s herbarium, the Botanical Museum later received the Herbarium Henschelianum (part of the Herbarium Silesiacum) with ca. 100,000 sheets.

As a result of these mergers and gifts, the Wrocław herbarium had acquired an extensive and significant collection of specimens from Europe (especially the Mediterranean) and the rest of the world. These were collected by botanists such as Hubert Winkler (a student of F. Pax the elder) in East Africa, Cameroon, Java, Sumatra and Borneo. In 1938, a collection of ca. 50,000 herbarium sheets (including numerous types) was donated to the Museum by Carl Adolf Georg Lauterbach, who travelled extensively in New Guinea and Melanesia. By 1914, the Herbarium had 540,000 sheets which, by 1939, had grown to ca. 600,000 sheets (Wiktor 2002; Wanat 2013). The oldest and most valuable collections of the Herbarium Silesiacum were those made by H.G. Mattuschka (1776 and 1779), A.J. Krocker (1787, 1790, 1814, 1823), A. Henschel (1830), a herbarium of fungi assembled by W.G. Schneider and an old herbarium of Paolo (Silvio) Boccone, a Cistercian monk, who moved to Wrocław in 1694 and donated his herbarium that consisted mainly of Mediterranean plants (Treviranus 1831; Rostański 1963). This herbarium is not mentioned by Stafleu et al. (1976), but is the oldest plant collection of a scientific nature in Poland. In 1935, the Herbarium Silesiacum housed over 80,000 sheets (Wanat 2013).

In autumn 1944, during the Second World War, German authorities evacuated all university botanical collections from Wrocław. The Herbarium Generale (combination of the various merged herbaria) was then located in Piotrowice castle near Kąty Wrocławskie (ca. 43 km S.W. of Wrocław), the Herbarium Lauterbachi in Siedlęcin near Jelenia Góra (ca. 95 km W. of Wrocław) and the other botanical sets in the garrison church in Oleśnica near Wrocław (ca. 27 km N.E. of Wrocław), which were unfortunately lost in a fire. The Herbarium Silesiacum was lodged, in turn, in the attic of one of the primary schools in south Wrocław (in the Tarnogaj district); however, it was not protected from destruction and the dusty and damp collection was rediscovered after the war unbound, mixed together with litter and broken glass (Wiktor 2002; Wanat 2013).

Shortly after the war, Polish authorities failed to discover traces of herbarium sets in the dilapidated buildings – these were found in the Piotrowice castle, Siedlęcin and south Wrocław only in 1946–1947, but only the Herbarium Lauterbachi was salvaged undamaged. The recovered collections were entrusted to Prof. Józef Mądalski, who was invited to Wrocław from Lviv (former Poland, now in the Ukraine). The war had damaged many of the specimens and repairs were successfully undertaken by Polish botanists. Rostański (1963) assessed the war damage in both herbaria (i.e. Herbarium Generale and Herbarium Silesiacum) as, after the war, only 200,000 herbarium sheets were discovered out of 600,000 that belonged to the University in 1939, together with 30,000 herbarium sheets from the former Herbarium Silesiacum which, in 1939, housed 80,000 sheets (it was confirmed then that the oldest Silesian flora sets of H.G. Mattuschka and A.J. Krocker had been destroyed).

Currently, the collections are estimated to contain over 515,000 sheets, including ca. 410,000 vascular plants, 27,000 bryophytes, 38,400 fungi and myxomycetes, 27,000 lichens and 12,600 algae (Mirek et al. 1997; K. Świerkosz, pers. comm., 2019). The herbarium WRSL has had a turbulent history and has enormous importance in the botanical history of Poland.

The aim of this investigation was to assess the value of the WRSL botanical collection using the genus Juncus as a case study. Type and other nomenclaturally and historically important specimens “hiding” in such under-appreciated collections are improtant for taxonomy, nomenclature and biodiversity studies. Using the WRSL herbarium, we address the importance of collections like WRSL as reservoirs of valuable data that are relevant to experts who are involved in taxonomic revision.

The Herbarium Generale of the mid-sized WRSL herbarium is rich in specimens relevant to the nomenclature of Juncus and contains 78 specimens (3.6% of all Juncus specimens examined, see Table 1), with an average of 11 sheets per fascicle (i.e. herbarium box). Seventy-six (of 78) of these historically-important specimens (types, original material and specimens collected at the type locality by the author of the name) were not identified as such before our study. This significant number of types highlights the significance of the analysed set and of WRSL more broadly, for the study of taxonomy and nomenclature (Sutory 1997). To put this into context, the approximate percentages of types stored in other historically-important herbaria are as follows: K (5%), W (3.6%), BM (2.6%) [cited from herbaria websites, which include the total number specimens stored]. Our study revealed that the Juncus set at WRSL is a valuable collection globally with respect to the number of historically- and nomenclaturally-relevant specimens. Often, specimens included are associated with research conducted involving a given group of plants in the academic centre housing collections. The majority of Juncus specimens (ca. 89.7%) date from before the Second World War and specialists studying the genus Juncus did not work at WRSL during that time. This suggests that the rest of the WRSL collection might also contain similarly high percentages of such historically- and nomenclaturally-relevant specimens.

As the genus Juncus is rich in species (311 species, Kirschner et al. (2002a, b)), we consider that extrapolation of our results to other genera is appropriate. We assume that descriptions of taxa new to science before 1946 were equally common within most taxonomic groups and specimens belonging to different plant genera/families were sent to the WRSL herbarium equally often.

Only a small fraction of global herbarium specimens had been computerised by the end of last decade (Lughadha and Miller 2009). Despite the recent acceleration of the digitisation of herbarium collections (as of early 2015, the number of scanned specimens within the world’s largest virtual herbaria was 18.4 million), we are far from fully digitising all collections (Seregin 2016). Even a small percentage (1–2%) of computerised specimens can drastically reduce research costs and help scientists focus on collections that are likely to contain the most information-rich specimens (O’Connell et al. 2004). In herbarium management, it is cheaper to produce and distribute scans than facilitate botanist visits (Seregin 2016). Digitisation is also important because young people who do not live near a natural history museum or herbarium can access natural history data and learn to use it and this early involvement in science may cultivate a love for the study of biology (Watanabe 2019). The continued digitisation of the WRSL herbarium (currently only 4.9% digitally available) will certainly reveal new material for botanists’ use.

Our results reveal the usefulness of lesser-known herbaria not only from a national or local point of view (Lavoie 2013), but also as a source of important collections and type specimens that are not duplicated in larger facilities (Snow 2005). For Juncus, only two of 78 nomenclaturally-relevant specimens identified here were cited by Kirschner et al. (2002a, 2002b), so 76 of the specimens in Table 1 were unknown before this study. Holotypes, isotypes and isolectotypes constitute 46.2% of all types (and other nomenclaturally important specimens) of Juncus recognised at the WRSL, highlighting the nomenclature relevance of the collection. Three specimens are particularly worth highlighting here: the holotypes of Juncus lomatophyllus Spreng. and Juncus capensis var. gracilior Buchenau and a syntype of J. oxycarpus E. Mey. ex Kunth were originally stored in Berlin (the herbarium of the Botanischer Garten und Botanisches Museum Berlin-Dahlem, Freie Universität Berlin). These were destroyed during the Second World War (Hiepko 1987; Kirschner et al. 2002a) and our discovery of duplicates in WRSL will help with the correct application of these names.

Duplicates of nomenclaturally relevant specimens are often considered to be less important than holotypes, lectotypes and neotypes. Duplicates, however, may differ in physical condition, material quantity, different annotations, labelling, specimen content (plant parts, for example, young fruit vs. only a flowering twig, male vs. female flowers in diclinous plants, with roots vs. without roots) or may even represent mixed gatherings (different taxa). An isotype of Juncus singularis Steud. (J.F. Drège 1604b) at WRSL, for example, is a much larger, leafy specimen with five inflorescences, as compared with other specimens at G, P, S and W, listed and pictured at plants.jstor.org (accessed on 16 Apr 2020). Annotations by specialists can be very useful in understanding taxonomic concepts: 23 WRSL Juncus type specimens were annotated by Franz G.Ph. Buchenau (1831–1906), a Juncus specialist whose work remains unsurpassed to this day (annotations included new determinations and/or ‘specimen authenticum’ indications and were made by him throughout 1874–1875, 1878–1879 and 1887; see the ‘Leg. et det.’ column in Table 1). Thus, some ‘ordinary duplicates’ at WRSL are helpful for understanding taxonomists’ thinking.

We also found that many of the historically- and nomenclaturally-important Juncus specimens stored at WRSL originate from South Africa (42.3%). This over-representation might be explained by the origin of the collection. German botanists (together with the British and the Dutch) were a dominant force in the floristic exploration of Africa from the 17^th to the early 20^th century. The WRSL herbarium is, thus, an important resource for international researchers working on the flora of that hugely biodiverse, but still under-explored, part of the world.

The history of German-Polish herbaria, including WRSL, is very turbulent. A detailed examination of Juncus, as a case study, confirms the value of the WRSL collection in historical terms. That a significant number of historically- and nomenclaturally-important specimens at WRSL was acquired passively (Juncus was of no special interest to German or Polish scientists at the time) suggests that more such specimens may be found within the collection for other genera. Digitisation and taxonomic revision of material will facilitate the confirmation of the richness of the collection.

Other large type collections contain well-preserved specimens, well-prepared catalogues (often available on-line) and are well-known to scientists. However, the WRSL collection is not only unique, as confirmed here, but not well-known to date.

Some Juncus type specimens, listed here, can be found easily in a large number of other collections. However, some are preserved only at WRSL because many types, previously stored in Berlin, were destroyed during the Second World War. Although we researched only a few parts of the WRSL collection, we are convinced that duplicates of many type specimens destroyed in Berlin can be found in Wrocław. Uncatalogued herbaria like WRSL with turbulent histories can be a source of collections important for the study of biodiversity.

We selected Juncus as a case study since the collection at WRSL covers the entire distribution range of the genus. Therefore, it likely reflects the general situation in other groups of plants in the herbarium.

Currently, many herbarium sets in Europe are still being catalogued (and many remain undigitised). However, many old collections are indeed valuable and their type and other historical collections have the potential to facilitate taxonomy and nomenclature and, in addition, enhance our knowledge of biodiversity through application of correct names.

We would like to thank Krzysztof Świerkosz Ph.D. (curator of WRSL) for making the Juncus collections available to us and for providing the latest statistics connected with the WRSL herbarium. We wish to thank Magdalena Mularczyk Ph.D. who consulted with us on matters related to the turbulent history of the herbarium in Wrocław. We also gratefully acknowledge Ewa Lenard Ph.D., who provided the materials connected with an old herbarium of Paolo (Silvio) Boccone. The project is supported by the Leading National Research Centre (KNOW) programme of the Wrocław Center of Biotechnology for years 2014–2018.