Introduction
In 1834, William Jackson Hooker, renowned Professor of Botany at the University of Glasgow, advertised a scientific association in the London-based Journal of Botany. In the report he introduced the Unio Itineraria, which was “extending its circle of research, and rendering most essential services to the cause of our favourite science” by sending travellers to far-flung parts of the world like Syria, Madeira, and South Africa to collect plant specimens.Footnote 1 Importantly, receipt of such material would only be possible by buying shares, so he requested “all friends of Botany to support the accomplishment of this undertaking by their subscriptions, a whole share at £3, and a half share at £1:10.”Footnote 2 This information had been communicated to him via an 1832 circular from the society’s directors, Ernst Steudel and Christian Ferdinand Hochstetter, from a town called Esslingen. This medieval town might not figure on most readers’ maps of Germany. Located near Stuttgart, then in the Kingdom of Württemberg and now part of the federal state of Baden-Württemberg in southwestern Germany, it was not known as a hub for scientific exchange, let alone a hub for much of anything at all. Yet, between the years of 1827 and 1845, Esslingen became well-known in the European scientific community for its role at the centre of a far-reaching trade in botanical specimens through the Unio Itineraria. As a local scientific society linking a provincial town to the rest of the world through biological material, the Unio is a unique object of study and offers a dynamic look into some under-researched aspects of nineteenth-century natural history.
The Unio Itineraria, also called the Esslinger Botanische Reiseverein, has not yet received much historical attention.Footnote 3 Karl Baur and Arno Wörz have written more biographical studies of the Unio, approaching the subject from their positions as botanists at the State Museum of Natural History in Stuttgart where large Unio collections are held.Footnote 4 The Unio is perhaps better known to botanists, as its plant specimens and associated data can be found in Vienna, Berlin, London, Paris, Basel, Washington D.C., New York, and beyond – in most large European and North American herbaria, according to Wörz. Moreover, many specimens are regarded as holotypes: the single representative that defines a ‘new’ species, which are immensely valuable in taxonomic terms.Footnote 5 In a town dominated by an agricultural and artisan class, the Unio was envisioned as a scientific society where continental naturalists would be sent on collecting expeditions funded by subscriptions. Donors or ‘members’ would receive botanical material in proportion to the amount contributed as dividends, what its founders termed a “joint stock company” for herbarium specimens.Footnote 6 The system devised by Steudel and Hochstetter closely resembled the arrangement of joint-stock enterprises most often associated with early European exploration, like the sixteenth-century British Muscovy Company or the seventeenth-century Dutch East India Company.Footnote 7 However, there are also traces of this model operating elsewhere. For example, Anna Simons has demonstrated how the London Society of Apothecaries administered commercial interests through collaborative production and subscription-based companies.Footnote 8 Denise Phillips, on the other hand, has shown how the German Society for the Spread of Natural Knowledge “proved to be an unworkable hybrid” of the types of subscription societies created to support scientific travel and missionary work respectively.Footnote 9 Nonetheless, the Unio’s employment of the joint-stock or subscription-based model implied that its goal was to establish a relationship between botanical trade, foreign travel, and science from Esslingen, facilitating access to specimens for a wider audience.
The foundation of the Unio can be placed amongst the general surge of local and regional scientific societies in Germanophone Europe in the nineteenth century. These societies usually originated from an educated bourgeois and petit-bourgeois class who dedicated themselves to the study of the local environment, local history, or antiquities.Footnote 10 In contrast to Britain or France, German scientific activity was less nationally organized – a legacy of its fragmented political history – which enabled a fruitful dialectic of professionalization and popularization in the natural sciences.Footnote 11 Not only did the German states offer more institutional and university positions for natural history to be practiced, the fine-meshed network of natural history societies “formed local centers of a privately organized scientific practice” with a wide socio-professional composition.Footnote 12 This meant that the structure of natural history in the German states was perhaps slightly more flexible toward those who would have been considered ‘amateurs.’Footnote 13 The scientific community remained relatively open to publishers, apothecaries, horticulturalists, physicians, and other professionals that might have been considered part of the educated (and merchant) class, leading to a complex associational life and a vibrant network of intellectual communication. More minor capitals and regional centres established natural history societies to make the point that Naturwissenschaft was no longer the monopoly of the learned estate.Footnote 14 As the natural sciences became professionalized during the nineteenth century, the term ‘amateur’ was increasingly used by academic elites to distance themselves from middle-class petit-bourgeois ‘amateur enthusiasts,’ collectors, dealers, or women, who often needed to turn science into a paid vocation.Footnote 15 Though some scholars have described this as a period where distinctions between amateur and professional were still in flux, the example of the Unio offers insight into the operations of actors on the margins of science, demonstrating how they established both scientific credibility and authority during their active years.Footnote 16 By visualizing regional hubs like Stuttgart, and smaller provincial towns like Esslingen, as crucial nodes of knowledge production about the world’s flora, it allows us to think more carefully about the social and geographical dimensions to the nineteenth-century sciences.
Recently, historians have been investigating the role of Germans who operated in colonial spaces under the auspices of other nations and empires, made possible by new scholarship under the theme of ‘Germans in the world’ and new directions in the study of German colonialism.Footnote 17 It has long been understood that imperial careering, alongside travel narratives or adventure novels, helped to fashion what have now been rather famously termed “colonial fantasies.”Footnote 18 However, more recent work has challenged the idea of colonialism as merely a fantasy prior to Germany’s acquisition of colonies in 1884, invoking concepts like soft imperialism, non-occupational imperialism, and “colonialism without colonies” variously to suit specific examples and geographies.Footnote 19 While Suzanne Marchand has argued, in the case of German Orientalism, that it was not “primordially or perpetually defined by imperialist relationships,” spaces outside of Europe could be sites where German national and imperial visions were articulated.Footnote 20 We know, for example, that collectors often participated in the more overt parts of the colonial experience – physical violence, racial oppression, or labour or resource extraction – and that important contributions made by Indigenous intermediaries were silenced. Likewise, adherence to European methods of taxonomy reveals the more nebulous ways that the Unio were complicit in the epistemic violence of European science.Footnote 21 Our case study of Christian Ecklon, who spent several years collecting in South Africa in the 1820s and 1830s, exemplifies the subtle ways in which Europeans could carry (or adopt) a colonizing mindset while in the field. We can see how endeavours like the Unio have the potential to offer “a snapshot of the different paths that might have led educated middle-class Germans to support activities that, later in the century, formed part of Germany’s drive to become a colonial power,” and reveal the tensions in establishing contact with the ‘exotic’ in the nineteenth-century German states.Footnote 22
In studying the Unio’s organization, finances, and publicity, we seek to establish how this constellation of provincial Germans fashioned and maintained transnational networks of science. The journals where these actors debated, advertised, and sold their specimens took on the role of a socially diverse marketplace, bringing together a slew of actors with the same goal: the acquisition of botanical specimens from around the world. Exchange took place between Europe’s metropoles and small spaces, between rural and urban environments, and amongst people of different classes. As no comprehensive archive of the Unio seems to have survived the Second World War, we use printed material from their primary outlet, the Regensburg-based scientific journal Flora, as well as other botanical publications and private correspondence from the German states and Britain to ascertain the Unio’s reach, impact, connections, and negotiations during its short associational life.Footnote 23 First, we will investigate the establishment of the Unio to map its networks and visibility, followed by a case study of one of the Unio’s collectors, Christian Ecklon, to understand the association’s practices of collecting and selling specimens. In the final section of the paper, we will look more closely at the Unio’s uptake in Britain. As an enterprise fundamentally concerned with the trade in affordable specimens and the scientific credibility necessary for that, we can see the Unio’s ambitions. They expanded their outreach both in terms of the spaces in which they collected and the potential markets where they could gain subscribers, which allowed them, ultimately, to sell more botanical material.
The Unio Itineraria and Provincial Science in the Early Nineteenth Century
The Unio Itineraria was established by Ernst Gottlieb Steudel and Christian Ferdinand Hochstetter in Esslingen in 1825. Both directors had relatively similar backgrounds and similar reasons for being in the area in the 1820s. Steudel came from a wealthy Esslingen family, earned a doctorate in medicine at the University of Tübingen, and became a senior medical officer back in his hometown. He had already published in botany before the founding of the Unio, most notably his internationally-known Nomenclator Botanicus.Footnote 24 Hochstetter, born in Stuttgart and educated at Tübingen in theology, became an instructor at the teacher’s seminary and the Esslingen town pastor.Footnote 25 Wörz assigns the Unio’s foundational idea to a growing interest in making education and science more accessible, a typical example of Tobias Scheidegger’s idea of “petit-bourgeois men’s science.”Footnote 26 The Unio aimed to counteract the prevailing trend that natural history belonged to small circles of museum directors or to the “rich and great” by making ‘exotic’ specimens from around the world the “common property of all friends of natural science with relatively little sacrifice for the individual.”Footnote 27 The foundation of the society was published in Flora in an “Announcement for Plant Enthusiasts,” informing readers that the directors had already located a young, experienced botanist ready to make the Unio’s first regional collecting journey. They suggested that if they managed to acquire the forty financial partners needed to fund the expedition, members would receive at least 200 species of well-dried alpine plants for the low sum of 1 Louis d’Or.Footnote 28 This initial enterprise seems to have been relatively successful; in early 1826, two announcements suggest further collecting endeavours and that a joint-stock company should be founded to allow the society to hire naturalists to undertake yearly collecting journeys.Footnote 29
Furthermore, Steudel and Hochstetter informed their readers that the Stuttgart Centralstelle des landwirthschaftlichen Vereins (Central Office of the Agricultural Association) had agreed to support them, sending invitations to agricultural and natural history associations across the state. There are several reasons why the Centralstelle would want to support the Unio. Because of an ongoing economic depression, food shortages, and famine, King Wilhelm I (often referred to as the Rex Agricolarum) became heavily invested in the more practical aspects of Oekonomie, the science that aimed at the improvement of agricultural productivity.Footnote 30 Phillips has shown that the global and intra-European plant trade prompted discussions around the utility of plant geography for Oekonomie. She details how new crops and garden plants were part of the development of a market-oriented, commercial agriculture and how an interest in new fruits and vegetables fuelled the growth of consumer society in the German states.Footnote 31 In 1833, for example, Unio collectors Wilhelm Schimper and Anton Wiest sent a box of grapevines from Kefalonia to the Württemberg Society for the Improvement of Wine, an arm of the Centralstelle.Footnote 32 European commercial and colonial expansion generated new questions about how agriculture in other parts of the world might be economically viable at home.Footnote 33 From the very beginning, the Unio marketed itself as an organisation which tried to enable the acquisition of plants not necessarily driven by idealized scientific or gentlemanly interests, but rather by practical financial restraints and a desire for improved agricultural productivity.
We can get an idea of the Unio’s reputation and publicity across Germanophone Europe from a member list published in the Correspondenzblatt des Württembergischen landwirthschaften Vereins (the Correspondence Paper of the Württemberg Agricultural Association) in 1826. It lists 14 honorary members, including Kaspar Maria Graf von Sternberg (Prague) and Franz Ludwig Baron von Welden (Vienna) – both keen botanists – as well as influential individuals from Stuttgart and other agrarian or natural history societies. Other members include a pharmacist in Aargau (Switzerland), professors of botany in Geneva, Kremenets, and Wrocław, and booksellers, apothecaries, bankers, or directors of botanical or horticultural gardens, amounting to 89 members in total.Footnote 34 A closer look at the member list reveals how the official aim of making its collections available to all was essentially limited to the wealthy middle class and the aristocracy. This supports calculations by Wörz: one share of 15 Rhenish florins (or guilder) would have amounted to nearly a month’s salary of a textile worker, whilst it was about 1.5% of the yearly salary of the Esslingen mayor.Footnote 35 Despite this, the countless supporting letters which highlighted the affordability of the Unio’s collections and its broad distribution demonstrate how they were fairly successful in their aims initially; many of the people listed above would not have had access to such plant specimens otherwise.
Although the first expeditions were much closer to home in the Alps and Istria, the Unio also set its sight overseas within the first year of its inception. They realized that finding trustworthy naturalists who were stationed either permanently or semi-permanently overseas would help “establish connections in the areas where European culture has already penetrated,” saving them the costly expense of investing money up front to send collectors abroad.Footnote 36 Here, German-speaking collectors become part of the settler colonial cultures of the United States and the British Empire. We see this, for example, with Stuttgart-born collector Carl J. Moser in the early 1830s. Educated as an apothecary’s aid, he travelled to Pennsylvania to start an apothecary business where he assembled collections of plants to send to Esslingen in his spare time.Footnote 37 The previously mentioned Wilhelm Schimper travelled to Algeria, Egypt, Sinai, and Ethiopia around the same time and settled in Ethiopia permanently.Footnote 38 Accounts of ‘adventurous’ journeys were also included in the Unio’s announcements. By reproducing harrowing accounts of near-death experiences, interactions with Indigenous groups, and the unfamiliar landscapes in colonial environments, Steudel and Hochstetter most likely sought to make their collections seem more ‘exotic’ and desirable to attract new subscribers. In an 1827 announcement, they informed readers that their collector Franz von Fleischer had arrived back to the German states with all his “treasures” of the flora of “the Orient,” having travelled throughout Illyria, Istria, Greece, Asia Minor, Syria, and Egypt. Alongside details on the more than 25,000 specimens of dried plants, the directors also included a three-page travel account of the journey, highlighting moments which revealed his capabilities as a collector, like the heights he reached collecting alpine moss specimens and his experience in an avalanche.Footnote 39 Keeping readers interested through gripping stories of adventure, the Unio capitalized on the popularity of travel literature, used here as a marketing tool to attract new members and the purchase of larger shares.Footnote 40 Regular announcements were used not just to give updates on the travellers, collections, and subscriptions, but also to remind readers of the benefits of receiving rare plants at a relatively cheap price – their selling point. However, it is in South Africa where the Unio took on a more overtly colonial role through its collector Christian Ecklon.
Christian Ecklon: Collecting in South Africa
Ecklon was born in present-day Aabenraa (Denmark), characterised both by Danish and German influences due to its geographical position. Although not much is known about his early life, he trained as an apothecary in German-speaking Kiel – in the northern portion of Holstein – while the sweeping territorial changes of the post-Napoleonic period were taking place. Though he has been attributed to Denmark in modern understandings, we can tentatively suggest that Ecklon grew up with both Danish and German; his remaining correspondence was written mostly in German and his scientific networks were rooted within the German states. Nonetheless, he found his way to the Cape Colony in 1823 as an employee of the Pallas & Polemann pharmacy at Strand Street in Cape Town.Footnote 41 Located “at the southernmost end of a great commercial and information highway,” the Cape was shaped by a range of commercial, political, military, and intellectual networks that had connected Europe to the Indian and Atlantic Ocean worlds since the seventeenth century.Footnote 42 The pharmacy became a well-known stopping point for naturalists who came to the Cape on their way to the East Indies, playing a considerable role in the production of knowledge about southern Africa’s natural history in the first half of the nineteenth century.Footnote 43 Knowledge of the local – whether of the colony’s climate, plant localities, Indigenous peoples, or its other collectors – was a precious asset, something which Ecklon himself would become to future collectors in southern Africa.Footnote 44
Although correspondence has not been located detailing how Ecklon became affiliated with the nascent Esslingen society, the new connection was promoted in Flora by 1827.Footnote 45 Entitled Exkursion nach dem Tafelberge auf dem Kap der guten Hoffnung (Excursion to Table Mountain on the Cape of Good Hope), the piece sought to introduce Ecklon as a Unio collector and to familiarize readers of Flora with the plants found on the iconic Table Mountain.Footnote 46 Less for the purpose of explicitly selling specimens and rather to attract new subscribers, it instead promoted what members of the society could expect in the coming months, offering “a guarantee of a permanent connection with the botanists of the Cape” and assuring readers that “collections are ready to be sent from Smyrna, Cagliari and the Cape of Good Hope.”Footnote 47 In a tone both whimsical and scientific, Ecklon explained what plants could be found at different heights of the mountain, as well as weather conditions, fauna, temperature readings, mineralogy, and a bit of local information – describing the famous ‘table cloth’ which often envelops the mountain and explaining his disappointment at a stretch of characteristic fynbos which had recently burnt. Hoping to drum up interest and new membership, this description of a hike on Table Mountain was certainly intended as an advertisement for the impending distribution of Cape specimens amongst shareholders. What remains conspicuously absent, though unsurprising, is Ecklon’s relationship to his Indigenous assistants or the knowledge he appropriated from their expertise. However, based on existing research, we can certainly assume that Ecklon did not collect alone and consciously omitted the contributions of his assistants in his reports.Footnote 48
Not long after, Steudel and Hochstetter sponsored the publication of a detailed list of Ecklon’s Cape collection which would be made available to subscribers.Footnote 49 Described as “very extensive” by Berlin-based scientific journal Linnaea, it contained many new genera and species which had not yet been scientifically named, alongside colour, location, and flowering times where possible.Footnote 50 When the collection was finally advertised in 1828, it had over 1000 different species of plants amounting to 6000-7000 copies for distribution. Ordinary subscribers would receive 200 specimens for 15 Rhenish florins, but one could also buy an entire set of 800 species for the cheaper price of 55 florins. Plants available to subscribers included “8 genera of Proteas with 26 species, including the magnificent ones: Leucadendron argenteum, Protea mellifera, Lepidocarpodendron, etc.,” 21 genera of grasses with 74 species, 14 species of Oxalis, and a “large abundance” of other types (Figure 1).Footnote 51 In the 1829 edition of Flora a Dr Schinzlein, a district court physician in Monheim, published an article on the quality of the Ecklon specimens. He ranked the 800 species he received from magnificent to excellent, very good, medium-good, and poor according to standards he developed while ranking the specimens of other collectors. Despite a portion of Ecklon’s specimens being in poor or incomplete condition, Schinzlein noted that the price was extremely cheap in relation to other Cape collections that were on the market: that of Dresden-based collector Franz Sieber or Ecklon’s future collecting partner, Karl Zeyher. He argued that “we find that the prices of the herbaria announced so far are so high that anyone without the means must forego owning them entirely,” reiterating how the Unio joint-stock concept was an affordable way to receive botanical specimens for that time.Footnote 52
Leucadendron argenteum, or the Cape silver tree, which is endemic to a small portion of the Cape Peninsula and now endangered. The specimen was collected by Christian Ecklon for the Unio Itineraria and is now held at the Royal Botanic Gardens Kew. Source: Leucadendron argenteum, Unio Itineraria 1828, at Royal Botanic Gardens, Kew. Catalogue no. K000353675, http://specimens.kew.org/herbarium/K000353675, accessed 11 June 2025. CC-BY 4.0 © RBG Kew.
Despite these relatively positive reviews, the Ecklon Unio collections also sparked some controversy. James Bowie, previously a collector for Kew Gardens who had settled permanently in Cape Town, publicly complained about the inaccuracies found in Ecklon’s list in the South African Commercial Advertiser. Particularly cutting, Bowie claimed that,
the student may often overrate his abilities, and imagine that he has done more for science than those who have preceded him, and that he alone has discovered novelties, while many of them exist in European collections, and are becoming what their professors call, old.Footnote 53
He stated that it would have been impossible for Ecklon to prove that of the 375 Coronariae and Irideae mentioned in his catalogue, 127 were new species, remarking that European botanists “might as well receive a list of so many Hottentot names, as those too often misplaced scientific ones.”Footnote 54 This comparison demonstrates not only Bowie’s potential disregard for Ecklon’s work, but also a wider contempt for Indigenous knowledge or common plant names. It is here that we see epistemic violence at work through a forceful adherence to European naming systems. Even a tyro, to use Bowie’s term, would have known that the classification of Coronariae, given by Linnaeus in his Methodi Naturalis Fragmenti (1738), was obsolete and now belonged to the order of Asphodelaeae of British botanist Robert Brown.Footnote 55 Bowie makes two important points. Firstly, that many Cape plants were already perceived as ‘old,’ as there had been a long-standing circulation of Cape flora since the mid-seventeenth century. For this reason, their market value was relatively low, suggesting less interest and lower prices for Ecklon’s collections. As Robert E. Kohler has remarked, institutions and collectors in Europe eventually decided they had enough material from one region and began to shift their attention to other parts of the world.Footnote 56 Thus, Bowie believed that Ecklon was purposely inflating his own accomplishments to sell Cape plants that, as Bowie claimed, already existed in most European collections.
Secondly, while botanists in the German states (and elsewhere) were busy trying to affix Latin scientific names to Ecklon’s plants, there was a moment where money could be made on alleged new species. The popularity of certain kinds of natural history specimens helped to create a larger market for collections of rare or unusual forms; the more species devised, the more they had to sell. Consequently, there was competition for scientific authority and the legitimacy that came with taxonomy, and thus also the worth of plant specimens. While an argument can be made that Ecklon might have been noticing the huge number of varieties extant in Cape plants – a region we now know has a high rate of endemism and plant adaptations – the supposed redefinition of plants already ‘discovered’ qualified him as a potential ‘species monger.’ Used later in the nineteenth century by Kew Gardens Director Joseph Dalton Hooker, the term applied to those (usually colonial collectors) who were out to make money by multiplying species. They often chased the prestige that came with the ‘discovery’ of a new species (their name as taxonomic marker), or it allowed them to continue selling their collections as ‘new.’Footnote 57 The Unio reacted defensively to such accusations. Steudel anticipated the kind of criticism that Bowie brought forward, maintaining in Flora that “since there is a complete lack of literary aids at the Cape one cannot reasonably argue with the author if some species already known and described in Europe appear to him as new.”Footnote 58 He continued that even his own modest library and herbarium made it impossible to correct more than a few glaring inaccuracies and that specialists in certain genera needed to take up the task as quickly as possible, to “draw attention to creeping errors and almost inevitable synonyms.”Footnote 59 However, Steudel and Hochstetter were not in unison in how they felt about multiplying species. In the process of determining and distributing Ecklon’s Unio collection, Hochstetter repeatedly accused Steudel of mihimism – applying ‘mihi’ (mine) in the first descriptions of plants and creating new plant names where there were already many synonyms.Footnote 60 In a letter to Bavarian botanist Carl Friedrich Philipp von Martius in 1842, Hochstetter accused Steudel of focusing not on “science” (die Wissenschaft) but rather on “money and fleeting fame” (das Geld und flüchtiger Ruhm).Footnote 61 This reveals a tension within the wider scientific community at the time. How could one achieve scientific credibility when there was much at stake, whether around the monetary value of specimens, the reputations of individual collectors, or the lasting prestige of a small group like the Unio?
The problem of synonymy and the declining interest in Cape plants seems to have been real: there was low demand for Ecklon’s Cape plants amongst the subscribers of the Unio.Footnote 62 This could have also been due to doubts about Ecklon’s reputation. For an author to appear before the scholarly world as simply the purveyor of a commodity would have been to sacrifice all claims to learned legitimacy; people who saw natural history specimens as profit-generating commodities could be quickly delegitimised as untrustworthy cheats by those in the upper echelons of science.Footnote 63 This is something Ecklon attempted to avoid by assigning his own Latin names to species, despite collecting for what was ostensibly a commercial enterprise. Judging by messages released by the Unio in 1829 and 1830, there were still complete sets of Ecklon’s Unio collection available for purchase. Attempting to sell off more shares, Steudel and Hochstetter used their influence to implore “young botanists, to draw attention to this probably never-to-be-repeated opportunity to obtain Cape plants so cheaply.”Footnote 64 It is impossible to know whether Ecklon was attempting to create more species for his own benefit, or what kind of conversations occurred outside of the pages of scientific journals and polite correspondence. By 1840, however, the Irish botanist and author of the Flora Capensis, William Henry Harvey, offers some insight into Ecklon’s reputation: “all Europe knows Ecklon […] at the Cape every one knows that Ecklon is a drunkard […] Ecklon is too an ignorant person […] I would have nothing to do with Ecklon.”Footnote 65 This attempt to discredit Ecklon as a serious collector highlights how scientific authority could be constructed not only in relation to education, but also through ideals of morality and scientific gentlemanliness. And, like many initially respected colonial collectors of the early nineteenth century, Ecklon spent much of his life afterwards “poor and [he] died as a pauper.”Footnote 66
Ecklon’s position within European scientific circles was complicated. He was a Danish-German petit-bourgeois (former) apothecary, imperial careering in a British African colony, who fundamentally depended on the market for botanical specimens to make his living. While he was supported and, when it came to it, defended by the Unio in what was largely a more forgiving scientific milieu in the German states, he received more scrutiny by those within Cape settler society and the British metropole. These slights were perhaps a mixture of class, competition, and potentially even national background. Operating between two different scientific worlds, Ecklon’s history as a collector is a stark reminder of the fickle realities of nineteenth-century ideas around scientific gentlemanliness and authority. Thus, it is worth investigating the Unio’s uptake in Britain, to parse out some of the subtle differences in scientific culture that would have affected Ecklon’s standing, or indeed that of the Unio, as a credible and authoritative scientific society in European science.
Advertising in Flora: Reaching Britain
After initial announcements on its foundation, the Unio maintained its printed presence in Flora, a scientific journal published by the Regensburg Botanical Society. Not only was it a key outlet for promotion, but it acted as a marketplace for the commercial trade in botanical specimens and as a space for the exchange of new scientific information coming in from across the world.Footnote 67 However, as the member list reveals, the Unio’s reach went beyond the Germanophone world into Britain.Footnote 68 What was ostensibly a regional, German-speaking organ reached British audiences through the auspices of William Jackson Hooker, Professor of Botany at the University of Glasgow and future director of Kew Gardens in London, and natural history agent John Hunnemann. Born in London though of German descent, Hunnemann sold botanical specimens, prints, and books from his business at No. 9 Queen Street, Soho Square until his death in 1839.Footnote 69 Hunnemann acted as “the most excellent Forwarder of the botanical treasures of England to the continent” and as the primary agent for German, Swiss, and Russian naturalists seeking contacts in Britain (and vice versa).Footnote 70 It helped, too, that Hooker read German. The two would collaborate, transmitting all things botanical to British audiences and making translations for British and German scientific publications. It is through this route that the Unio managed to find a wider, Anglophone audience.
The German states had a particularly good reputation in botanical collecting and specimen-making in comparison to Britain, making the prospect of the Unio much more enticing. This was especially the case for the late eighteenth and early nineteenth centuries, when Britain lacked suitable educated experts for its imperial project and profited from the large number of German naturalists, engineers, and forestry experts working in its colonies.Footnote 71 Important British naturalists commented often on the abilities of their German counterparts. The Scottish garden designer John Claudius Loudon was quick to offer praise in the 1834 introduction to the Magazine of Natural History that “the continent of Europe, and more especially France and Germany, may be considered as having been long in advance of Britain in natural history pursuits.”Footnote 72 Quoting from Flora, Hooker published an account in the Edinburgh Journal of Science “of a society lately established in Germany” in 1827 which sent “zealous and properly educated botanists” to collect “rare plants” funded by paid membership contributions, inviting “naturalists of other Countries, and especially those of Great Britain […] to contribute towards so laudable an object.”Footnote 73 He lamented the “almost unconquerable antipathy to the operation of gathering and drying plants” in Britain and stated that “the French and Germans far excel us in this important department of a botanist’s pursuits […]. In Germany, especially, the art of preserving plants is carried to a very high degree of perfection.”Footnote 74 Putting his trust in the project, he reported “the number, rarity, and beauty of the specimens” in the collections he had already received from the Unio. As Hochstetter confirmed, Hooker held two stocks in the Unio and would send comments on the moss specimens – his area of expertise.Footnote 75 From these descriptions, it could be suggested that the Unio was not a provincial society of alleged amateurs engaging in specimen dealing, but rather a group executing highly technical, skilled botanical work.
Though the early nineteenth-century world was becoming more intimately connected through new technologies like the steamship, botanical communication between Britain and the German states was still relatively embryonic and fundamentally dependent on the translations made by people like Hunnemann. If British naturalists were to be informed of new collections or treatises by German naturalists, they needed to appear “in english dress, for without it, there would be little chance of its coming to the knowledge of british botanists.”Footnote 76 Even by 1843, it was noted that “the botanical intercourse … [had been] till now very scanty,” suggesting that some progress had been made but clear channels had yet to be established.Footnote 77 Yet, looking closely at the British botanical journals of the time, it is perhaps surprising how actively the Unio was being promoted. In the first volume of the Botanical Miscellany (1830), a short report on “the German botanical society, established for the purpose of sending collectors to different countries” was published, offering updates on the various collectors of the Unio and their available plants, all translated by Hunnemann.Footnote 78 We see again the relationship between state and society, as it was advertised that all subscriptions went through the Württemberg Centralstelle. On multiple occasions, Steudel’s “useful” Nomenclator Botanicus was referenced, and Flora was listed in a catalogue of botanical works. Hooker mentioned the Unio on several occasions, praising it for delivering “the most essential services to the cause of our favourite science” and calling on its need for additional funds.Footnote 79 Through scientific journals, knowledge of the Unio made it as far as India, where East India Company botanist Robert Wight suggested it as a potential model for a new society based in Madras.Footnote 80 The Unio’s connections to Hunnemann and Hooker, and the translation of their material into English, meant access not just to Britain but the entirety of the British Empire.
However, expanding into Britain sometimes meant dealing with new cultural norms in the practice of natural history. Through Ecklon’s experiences we can see the emergence of a gap between the supposed ‘amateur’ and ‘professional.’ A small interaction about an 1828 specimen exchange can perhaps help shed light on this difference. Ecklon appealed to Hooker in Glasgow about determining his considerable Cape moss collection, since Hooker had established himself as the premier scholar on mosses, liverworts, and ferns.Footnote 81 Realizing he had neither the knowledge nor time to devote to classifying cryptogams, Ecklon was desirous to place it “into the hands of the first connoisseur of Mosses in Europe.”Footnote 82 Ecklon assured him that no other naturalists had received assemblages of his mosses and lichens other than Kurt Sprengel, an eminent naturalist and physician at Halle. Ever the promoter of his work, Ecklon hoped that Hooker would publish a Cryptogamic Flora of South Africa based on his collections. To Ecklon, an exchange of this kind would not be without retribution. He requested 40 guineas in payment for the mosses and recommended Hooker distribute them amongst other British naturalists to recover the funds of the original purchase. The majority of Unio collectors were reliant on financial transactions like these to support themselves, Ecklon included. Though specimen exchanges were a routine practice of naturalists since the early modern period, by the nineteenth century an exchange of this kind revealed a demarcation between naturalists and “mere collectors” who aimed to profit off the specimen trade.Footnote 83 Viewing the Unio from Britain, the relationship between scientific credibility and the value of specimens becomes clear: despite being lauded for the quality of their work, the Unio could lose its appeal once its plants had been distributed and further financial compensation was requested. These categories of ‘amateur’ and ‘professional’ were under constant negotiation, revealing the tensions inherent in this period in natural history.
As much as British science had benefitted from the Unio, British scientific journals were helpful in signalling its end in the mid-1840s. By 1846, the London Journal of Botany printed a forward to an address by Steudel and Hochstetter to its members, praising the Unio:
The Unio Itineraria has done a great good to Botany, and we have done every thing in our power, both by individual subscription and by inducing others to aid in so praiseworthy an object; and we are aware of the great difficulties it has had to encounter.Footnote 84
The “great difficulties” Hooker alludes to are various. Already in 1841, Steudel and Hochstetter made a note of appeal asking members to buy more subscriptions, which would “speedily enable” them to send Wilhelm Schimper additional funds that he had requested in Ethiopia (Figure 2). According to the directors, it would otherwise be “utterly impossible to send him any more money.”Footnote 85 Unfortunately, this was a typical situation in natural history partnerships and why trust was essential when funding collectors abroad. Schimper, who did not deliver on the requested number of specimens, nonetheless continued to ask for money and material from the Unio, which left them in financial difficulty.Footnote 86 The limits of the Unio’s approach were also tested by (and ultimately collapsed in the face of) the deaths of several of their sponsored collectors. Indeed, by the time of Hooker’s appeal, the association had largely disappeared. Internal differences about the distribution of work, the mihimism debate, and rising costs in a time of political turmoil in Europe led to the decline of the Unio sometime between 1845 and 1847. The same edition of the London Journal of Botany noted that in France one Gaetano Durando had opened a comptoir Botanique for the sale and exchange of specimens “on a similar kind of business to that of Messrs. Hochstetter and Steudel,” although their joint-stock model was not carried over.Footnote 87 In a similar attempt, the Basel Natural History Society published an appeal in 1843 that a joint-stock company had been founded to fund the collecting journey of Emanuel Meyer to Mexico. However, the society only sold six stocks, and Meyer did not travel further than Texas.Footnote 88 The Unio did not signal the end of such local and regional societies, rather it became increasingly difficult for them to seriously contend with the emergent class of ‘professional’ botanists in universities and botanic gardens.
Senecio steudelii sent from Wilhelm Schimper in Ethiopia with the Unio Itineraria’s typical label and carrying Steudel’s name, distributed in 1842 and held in the Natural History Museum, Vienna. Source: Senecio steudelii Sch.Bip. ex A.Rich, at Natural History Museum, Vienna. Herbarium W. accessed via GBIF.org on 11 June 2025. https://www.gbif.org/occurrence/1848995430. CC-BY 4.0.
Conclusion
By the end of its approximately twenty-year run, the Unio had sent travellers far beyond the borders of the German lands, from Chile and Brazil to the Caucasus, South Africa to Australia, Ethiopia to Cincinnati. In so doing, they brought the flora of the globe to a small pocket of Württemberg for distribution throughout Europe, hosting a wide professional, socio-economic, and transnational base of support concerned with the sale of botanical specimens. While we can certainly say that the Unio collapsed when it did because of its financial, practical, and ideological difficulties, by the 1830s and 1840s a new generation of ‘professional’ botanists began to change the standards for what counted as wissenschaftliche botany in the German states (or ‘philosophical’ botany in Britain).Footnote 89 As Denise Phillips has shown, “they looked askance at the previous generation’s fascination with systematics, Naturphilosophie, and Humboldtian natural history” while sharply criticizing “the (to their eyes) disorganized empiricism of many contemporary fellow naturalists.”Footnote 90 As she highlights, they had a strong disregard for “Germany’s emerging low scientific culture,” a place where the Unio had originally tried to stake its claim.Footnote 91 Some of the problems that the Unio and its collectors encountered – the mihimism debate, the accusation of excess species for commercial gain, and public questioning of scientific or personal virtue – were very much a reflection of that period in natural history which the new generation were quick to condemn.
Nonetheless, in its tenure the Unio’s joint-stock approach and philosophy of openness to all friends of natural history caught the attention of famous naturalists like William Jackson Hooker and ordinary apothecaries, booksellers, merchants, and other artisanal or trade professionals alike. The span of their network, helped by continuous promotion in Flora and other leading scientific journals, meant that Esslingen became a recognizable name in the distribution of global plant specimens. Importantly, this provincial town had a small but crucial role to play in nineteenth-century botany: it challenged traditional ideals of gentlemanly science, showed how commercial interests and marketing drove exchange, and illuminated how scientific authority was negotiated. As our analysis has revealed, despite its short existence, the Unio left a clear mark in European scientific publications and herbaria, demonstrating how botanical collections could be assembled and how the discipline of botany as we know it emerged. The Unio also sent its German collectors into colonial environments where they benefitted from the asymmetrical power-relations of colonial spaces and where local intermediaries and their knowledge were appropriated and erased. By adhering to European standards of collection and taxonomy, they helped to form imperial visions of the plants that they so desperately desired for their collections – like any other European empire of the time. Science was one of the best conduits by which any European could participate in empire.
The Unio Itineraria was a short blip in the history of natural history in the German states, but its commercial ethos and international reach make it an important point of enquiry for scholars interested in histories of Germany, science, and natural history collections. For the most part, the Unio’s directors and collectors have remained marginal in these historiographies. The most well-documented is perhaps Friedrich Welwitsch. Commissioned to collect in Portugal, the Azores, and the Cape Verde islands for the Unio in 1839, he was later appointed as naturalist in a state-sponsored exploration of Angola where he ‘discovered’ the infamous Welwitschia mirabilis for which he is named – arguably one of the most important botanical finds of the nineteenth century.Footnote 92 We also know that Ernst Steudel sold his first private herbarium of 15,000 species to English botanist Henry Borron Fielding in 1835 (now at Oxford University) and sold his second herbarium of 20,000 species to Albert Belhomme de Franqueville in 1856 (now at the Musée d’histoire Naturelle in Paris).Footnote 93 However, much of the identified Unio collections still reside close to Esslingen: some a short trip down the Neckar River in the State Museum of Natural History in Stuttgart and others further upstream at the University of Tübingen. Although the Unio as a scientific association slowly disappeared from memory, the plant specimens amassed by its collectors survive in countless herbaria and museum collections around the world – a testament to its reach.
Acknowledgements
We are extremely grateful to Harald Fischer-Tiné, Mikko Toivanen, Monique Ligtenberg, and the colleagues who workshopped this paper at the Chair for History of the Modern World PhD Colloquium and Internal Colloquium at ETH Zürich for offering thoughtful commentary on earlier drafts of this paper. We would also like to thank Gijs Dreijer and Iva Pesa at Itinerario, as well as the two anonymous reviewers, for their generous time and incisive feedback.
Open access
