Taxonomy and Arboretum Design Scot Medbury In the second half of the nineteenth century, arboreta joined natural history museums and zoological gardens as archetypal embodiments of the Victorian fascination with the natural world. Grouping plants by type is a familiar practice tions. This is especially problematic when the in North American gardens where small, sepa- concept is applied to a plant collection that rate collections of maples, oaks, or other gen- strives to be all-inclusive. The arboretum era are common features. Although it is now projects of the Olmsted landscape architec- unusual to follow a taxonomic scheme in the tural firms illustrate some of these problems layout of an entire garden, such arrangements and also exhibit how changes in plant tax- were the vogue in nineteenth-century botani- onomy were expressed in the landscape. cal gardens and arboreta. The plant collections Historical in these gardens were frequently grouped into Background families or genera and then planted out along The historical antecedents for arranging plant a winding pathway so that visitors encoun- collections taxonomically include the first Eu- tered specimens in a taxonomic sequence. ropean botanical garden, the Orto Botanica, Growing related plants together, in effect, founded in Pisa in 1543. The plants in this gar- organizes a collection into a living encyclope- den were grouped according to their medicinal dia, allowing for comparison of the character- properties and, by the end of the sixteenth cen- istics of species within a genus or genera tury, by morphological characteristics as well within a family. By planting related taxa in an (Hill 1915). As the science of botany advanced evolutionary progression, the more compli- during the Renaissance, the practice of storing cated sequential taxonomic arrangement re- herbarium collections in a taxonomic order veals the ancestral affinities of modern floras. developed, and this probably contributed to Good examples of this display theme are the the practice of arranging living collections in a "order beds" of herbaceous plants at gardens similar fashion. like Kew and Cambridge, which have long Following the publication of Linnaeus’ com- provided botany students with a compact syn- prehensive plant classification system in 1753, opsis of the plant kingdom arranged in botanical taxonomy changed radically, and taxonomic sequence. taxonomic gardens quickly followed suit. Wil- Despite the educational advantages, there liam Aiton used the Linnaean system in laying are significant horticultural and management out the original nine-acre botanical garden at problems that result from the application of Kew in 1760, as did the Reverend Erasmus taxonomy to the layout of a garden. Because Darwin (grandfather of Charles Darwin) when plant families tend to be ecologically heteroge- designing his private garden at Litchfield in neous, they require a variety of cultural condi- England (Simo 1988). 14 This plan, which illustrates the entry on botanic gardens m Liberty Hyde Bailey’s 1914 edition of the Standard Cyclopedia of Horticulture, reflects taxonomy’s role as the standard method of organizing plant collections m botanic gardens. In 1759, the French botanist Bernard de order, these were (1) the system of the Swiss Jussieu became dissatisfied with the Linnaean botanist Augustin Pyramus de Candolle, system while laying out a taxonomic garden at which was based on rather different principles Versailles. Jussieu began moving plants around than that of Jussieu, although the main differ- in pots in an attempt to express an arrange- ence might seem to be in the plant with which ment that reflected "genealogical" relation- the sequence of flowering plants starts- ships. Linnaeus himself had allowed that this Dutchman’s-pipe (Aristolochia) for Jussieu, was the goal of botanists although he had not and buttercups (Rananculus) for Candolle; (2) been able to provide more than outlines for the system of George Bentham and Joseph such an arrangement. Bernard’s arrangement Dalton Hooker, published in England between was further developed by his nephew Antoine 1862-1883, and in some ways an elaboration of Laurent de Jussieu, and his classic Genera the Candollean system; and (3) the post-Dar- Plantarum fairly soon gained broad acceptance winian system of Adolph Engler and Karl in Europe and became the basis for taxonomic Prantl, published in Germany between 1887- arrangements in gardens. 1915 and the first widely accepted system to be Following Jussieu’s work, three successive based on evolutionary progression. systems of classification have been principally In order to appreciate the progression of employed in the layout of sequentially ordered plant families in taxonomic gardens, it is first taxonomic plant collections. In chronological necessary to understand the placement of the 15 gymnosperms and subdivisions of the an- tems was not intended to show evolutionary giosperms (i.e., monocotyledons and dicotyle- progression. However, they did attempt to re- dons) within each of these classification flect their authors’ general ideas of the progres- systems. The sequence of dicot families is es- sion of morphological complexity. Jussieu’s pecially important, for although the pre-Dar- arrangement, as far as can be ascertained, winian systems of Candolle and Bentham and forms a basically linear sequence, but the Hooker began with the polypetalous (many- Candolles and Bentham and Hooker were ada- petalled) buttercups and magnolias, Engler and mant that plant relationships did not follow a Prantl’s dicot sequence commenced with the linear sequence, although the printed page willows and birches, whose apetalous (petal- forced such a sequence on them. Most plant less) flowers they considered to be more primi- classification systems appearing after the work tive. Both the Candolles (Augustin as well as of Charles Darwin and Alfred Russell Wallace his son Alphonse) and Bentham and Hooker have been predicated on an understanding of placed the gymnosperms between the mono- descent and evolution and, therefore, have cots and dicots because they thought that gym- tried to establish "evolutionary" relationships nosperms really were very complex organisms, among plants. In the first of these phylogenetic just like dicotyledonous trees, whereas Engler systems, such as Engler and Prantl’s, plant and Prantl placed them first, as the purported families were placed in a sequence beginning progenitors of the angiosperms. with the most primitive plants and ending The sequence of families in Jussieu’s, with the most advanced. This is still the case Candolle’s, and Bentham and Hooker’s sys- today, although a veritable forest of evolution- Contour plan of the Derby Arboretum, 1839. The arboretum path that winds around the peripherys concealed from the mam walk at the center by thick evergreen shrubbery and six- to ten-foot berms. From } C. Loudon’s catalog, The Derby Arboretum, published m London, 1840. 16 ary "trees" has been produced. Each tree the entire collection, and then leave by the purports to show the complexity of the rela- same gate without retracing their steps. tionships between plant families that cannot Loudon employed the "gardenesque" style be accomodated by the linear sequence of the (which he created and advocated) when plant- printed book. ing the arboretum, displaying the trees singly with sufficient room for each specimen to de- The Derby Arboretum velop without touching others. Such careful It was to the Candollean system that the planning notwithstanding, the arboretum was English author and garden designer John intended to be torn up and replanted every few Claudius Loudon looked when laying out the decades, in order to remove outsized trees and Derby Arboretum in England in 1839, the most to permit the addition of new taxa (Loudon influential of the taxonomically arranged Brit- 1840). ish gardens. Early in his career Loudon had be- The Derby Arboretum greatly impressed come intrigued by the novel marriage of both the American landscape architect science and landscape beauty that a taxonomic Frederick Law Olmsted, Sr., and his friend and garden presented (Simo 1988). In 1803 he mentor, Andrew Jackson Downing, America’s seized upon Jussieu’s system as the organizing first native-born professional landscape structure for a large arboretum and flower gar- designer and most influential transmitter of den at Scotland’s Scone Palace. In 1811 he rec- contemporary English design for American ommended a similar "living museum" for the use. Both men, when given the opportunity to city of London, with plantations arranged by design public parks, included taxonomic arbo- the Linnaean system in one area and by reta in their proposals, drawing heavily on Jussieu’s system in another. Neither the Scone Loudon’s writings and his seminal design for Palace nor the London garden materialized as the Derby Arboretum. envisioned. But with the taxonomic design for North American Derby, Loudon brought the arboretum into a Examples new era, where it joined the natural history North America’s first botanical gardens were museum and the zoological garden as an arche- planted without particular attention to taxo- typal embodiment of the Victorian fascination nomic or other thematic arrangements. The with the natural world. continent’s first proposal for a taxonomically The Derby Arboretum was designed to be arranged garden appears to have been made in viewed in a prescribed sequence. This concept 1839, for Nova Scotia’s Halifax Public Garden, drew on the eighteenth-century English tradi- followed closely by a design by Downing for a tion of emblematic landscape gardens such Derby-like arboretum in Boston’s Public Gar- as Stourhead, where statuary and classical den, probably in 1841 (Zaitzevsky 1982). But it temples, as they were revealed sequentially to was Olmsted and Calvert Vaux’s inclusion of a the viewer, were intended to call up specific taxonomic arboretum in their 1858 "Green- ideas and allusions, usually from classical his- sward" plan for New York’s Central Park that tory or poetry. At Derby, however, a new para- became the most significant early proposal, digm was evoked, that of science.