The manufacture of species:
Kew Gardens, the empire, and the standardisation of taxonomic practices in late 19th century botany
Christophe Bonneuil. Centre Koyré, CNRS, Paris
This is a working version of the following article (please go to the original published version for quotes and paginations):
Bonneuil C., "The Manufacture of Species: Kew Gardens, the Empire and the Standardisation of Taxonomic Practices in late 19th century Botany", in M.-N. Bourguet, C. Licoppe et O. Sibum, dir., Instruments, Travel and Science. Itineraries of precision from the 17th to the 20th century, Routledge, 2002, 189-215.
This paper is about the creation of universals and the maintenance of order in the field of systematic botany during the age of empire. More precisely, it explores how the practice of broadly circumscribing species, or in other words, the broad and variable species concept, became dominant in the practice of taxonomy in the second half of the nineteenth century, and how such broad species were established and given authority.
By the mid-nineteenth century, it seemed that no consensus could ever be reached between botanists concerning the delimitation of species and how this should be done, not to mention more ontological issues opposing evolutionists and creationists. A tremendous controversy arose between those who adopted a broad species concept — “splitters” — and those who preferred narrowly delimited species — “lumpers”. At the methodological level moreover, the right criterion to distinguish a “true species” from a mere variety was hotly debated between those who valued the study of living plants, and those who valued the comparison of dried forms. By the 1880’s and 1890’s, professional botanists working in huge herbaria (especially at Kew Royal Botanic Gardens near London) had largely impose their views:
a) the broadly-circumscribed species (and genera) became the standard for the delimitation of species (and genera);
b) the herbarium was recognised as being the essential tool of the taxonomist (rather than field observations or garden cultivation) and the comparison of dried specimens became the major criterion for deciding the circumscription of species;
c) a particular nomenclatural practice known as the ‘Kew-rule’, where the original specific epithet is not necessarily conserved when the plant is transferred to another genus, was widely followed.
This chapter examines how these three norms for species naming and delimitation came to rule taxonomic practices in the second half of the nineteenth century, and why they appeared, to such leading professional systematic botanists as Joseph Dalton Hooker (1817-1911), George Bentham (1800-1884), Alphonse de Candolle (1806-1893) and Asa Gray (1810-1888), as the only way to maintain order in the field of botanical knowledge, to ensure its progress and epistemic steadiness, and restore its declining status in the hierarchy of disciplines. The first two sections sketch the situation of taxonomic botany in the middle of the nineteenth century, and the debates on species delimitation. The third section underlines the role of Joseph Dalton Hooker in leading a crusade against the narrow delimitation of species. The fourth and fifth sections examine how professional botanists at the head of huge public herbaria enriched by expanding empires turned their herbaria into metrological institutions that imposed the broad species concept, by controlling the production of new names and setting standards in the practices of classification. They edited colonial floras, monographs and other unprecedented compilatory works. These huge enterprises prepared the grounds for a division of labour amongst botanists, and were (reasons for and) tools to stabilise names and to standardise practices. The final section reflects on Botany’s and the British Empire’s need for standards.
The proliferation of practitioners and species: a problem of order and authority in 19th century systematics
In the 18th century, systematic botany, the activity of naming and describing plants and classifying them into groups according to degrees of difference and similitude, was deeply related to the encyclopaedic project. It appeared as one of the most successful branches among the sciences, the nearest to its final goal.1 It had set principles which were adopted not only in the other branches of natural history (zoology, mineralogy), but also in other domains in science, especially chemistry and medicine. Botany was considered a most highly philosophical pursuit. Linnaeus’ (as well as Adanson's and Jussieu’s) insistence on explicit rules, predictivity, abstraction, numeration, clarity and neutrality of language resonated very strongly with the geometrical, quantifying and rationalising spirit of the enlightenment.2 Systematics could still by 1750 believe in completeness, a goal which appeared unachievable in the following decades, due to the rapid increase of specimens brought to herbaria by European expansion in the 18th and 19th centuries. Linnaeus’ Species Plantarum of 1753 described 5,890 species in 1,097 genera.13 One century later, the Candolles’ Prodromus described 58,975 species in 5,134 genera (dicotyledons only). In 1883, Bentham and Hooker’s Genera Plantarum estimated that there were 93,605 species (phanerogams only).4 This led, in the early 19th century, to a descriptionist shift that made systematic botanists appear as quibblers.5 In 1833, a phrenological study from Hewett Cottrell Watson (1804-1881) — who was also a botanist — illustrated the declining status of botany. It stated that, relative to other scientists, the heads of leading botanists were smaller in areas where the higher intellectual activities were carried out.6 Though it remained appealing for colonial actors and helped the professionalisation of Botany, the creed of a general inventory of natural productions of the world had, by the mid-nineteenth-century, lost its philosophical prestige.
More deeply, this massive specimen influx also constituted a dramatic epistemic challenge to 18th century classification systems. Most new specimens came from extra-European areas, whereas systems likeLinnaeus’ and Jussieu’s were largely the product and the rationalisation of European folk classifications. There was a relatively limited number of tropical species known in Europe before the end of the eighteenth century. Bringing extra-European and extra-temperate forms into the eurocentric frame of an existing classification represented a huge challenge. This tension is today revealed by statistical data on the distribution of species into genera. First, a tendency to create more genera (revealed by lower numbers of species per genus) is evident in families important in Classic and European folk economy and culture (such as Gramineae), as compared to tropical families or to temperate families with little economical and cultural relevance (such as Cyperaceae). Also evident is the typical ‘hollow curve’ distribution of species into genera in large cosmopolitan families :a few genera (crafted in the time of Tournefort, Linnaeus and Jussieu) are overcrowded with species, whereas numerous genera (crafted in the 19th century) contain no more than one or two species.7 This clearly hints at the conservatism of leading nineteenth-century botanists (with access to the resources of huge collections at the centre of expanding empires), as they tried to fit new exotic forms into the old genera inherited from the great 17th and 18th century botanists, which supposed, as we shall see to impede local botanists from the periphery (sometimes better placed to avoid this eurocentric bias) from creating “too many” new species and new genera.8 The enormous number of exotic specimens arriving in Europe was therefore not only a quantitative, but also a qualitative challenge to an established eurocentric taxonomic order.
Not only new species and specimens were proliferating, but also botany pratictioners. In the time of Linnaeus and the Jussieus, botanizing in European countries was done mainly by gentlemen of science or by students herborizing with their professor. The botanical exploration of remote regions of the world was done mostly by protégés indebted to their scientific patrons.9 The old regime of botany was threatened in the nineteenth century when natural history became very popular, not only in the upper and middleclass, but also in the upper working class. Local societies flourished. Botany was now practised by people of diverse social and educational backgrounds, motivations, and interests and practices, etc.10 European expansion brought overseas thousands of people that practised botany in remote settings. These agents of empire (Scottish doctors, adventurers, missionaries, soldiers, settlers…) had their own agenda. Few of them were ready to use the Latin and were easy to bend to the discipline of a division of labour between collectors and armchair professional naturalists.11
This endless accumulation of newly discovered living forms due to European expansion and to the multiplication of practitioners made the 18th century dream of a completion, bit by bit, of the inventory of nature a problematic enterprise.12 The anarchic increase of (‘good’ or ‘bad’) species challenged the way in which taxonomic statements had been until then validated and communicated. New actors and new specimens were not readily disciplined into botany’s Ancien Regime. The linnaean canon, for instance, by which a twelve words diagnosis could characterise a species and distinguish it from all others, was now “becoming quite inadequate to the requirements of the science”, because it would constantly have to be refined and reframed so as to take into account all the new species discovered since Linnaeus and Willdenow.13 Furthermore, in the middle third of the century, botanical journals became so numerous that it was impossible, even in the richest libraries of Kew or the Paris Museum to gather all the information necessary to identify quickly and correctly name a specimen or to write a monograph of a genus or a family.14 The cumulative nature of botany was at stake. Bringing order in the field of botanical statements and publications had become a central problem. In the 18th century naturalists viewed themselves as revealing the order of nature. By contrast, mid-nineteenth-century monographers seemed concerned rather with bringing some order in the chaos of previously published literature. Throughout the latter half of the 19th century, flora-workers and monographers introduced their work in similar ways : “(the botany of India) presents a perfect chaos of new names forwell-known plants, and inaccurate and incomplete descriptions of new ones” or “Es schien mir (...) eine lohnende Aufgabe zu sein, die bis jetzt bekannten Arten dieser für die Technik so überaus wichtig gewordenen Pflanzengattung möglichst vollständig zu vereinigen und mit Hilfe dieses Materials in das noch bestehende Chaos Ordnung und Licht zu bringen."15
The case of the genus Landolphia illustrates this tendency towards species inflation and the difficulty to make commensurable a crowd of heterogeneous statements from various actors. The Landolphia are Apocynaceaes growing in Africa and Madagascar. The first specimen that reached Europe was collected by 1787 in the kingdom of Oware (South West Nigeria) by Palisot de Beauvois, a gentleman naturalist who accompanied a French military expedition headed by Captain Landolphe. After examination in the herbarium of the Muséum National d'Histoire Naturelle, Palisot de Beauvois described it in 1806 as Landolphiaowariensis.16 In 1844, only three more species were described, but under two different genera (Landolphia andVahea) that were only later united (under Landolphia) in Bentham and Hooker’s Genera plantarum.17 In East Africa, Dr. John Kirk had observed some Landolphia and their elastic gum during the Zambezi expedition with Livingstone (1858-64). Appointed British Consul at Zanzibar a few years later, he studied these plants further and provided Kew with specimens from the coast near Dar-es-Salaam. As a good agent of the new British moral imperialism in Africa, he worked hard to make trade in rubber replace that in slaves in the East coast.18 The scramble for Africa, and more specifically, the search for African rubber yielding plants, suddenly focused attention on Landolphia. Several species produced good rubber and provided a great deal of the African rubber, which represented about one third of the world trade in the last two decades of the century.19 Landolphia therefore became an object of intense interest on the part of travellers, traders, civil servants in African outposts, etc. During the African rubber boom (1870-1914) when natural rubber resources were wildly depleted, several expeditions were organised in Western and Central Africa to find sources of rubber.20 This brought hundreds of new specimens in European herbaria, and saw many diverse actors — explorers, military men, military physicians, missionaries, traders, colonial officers, etc. — claim to have discovered a new species. Landolphia also became a hot topic for closet naturalists at home: parallel to the economic boom of rubber in Africa, one can observe a boom in the botanical literature.21 But when studying African rubber plants, even those happy few professional botanists who had access to large libraries and herbaria in Kew, Paris and Berlin (the metropolis of ruling colonial powers in Africa) faced great difficulties. They had to “navigate” in a poorly ordered field of statements—sometimes contradicting each other—about landolphias (concerning their appearance, distribution, specific identity, economic value, etc.). These statements were published in many different places and genre such as travel narrative, administrative reports or economic correspondence, local publications, etc., rather than in the major and readily accessible botanical periodicals.