5. Metodología (Página: 23)
6.4 Experimenting with Specific Properties
The Flora Tasmaniae contained 2203 species, identified, named and described from dried specimens collected in the field.66 The project also involved examining all the Australian plants held in London herbaria, particularly at Kew and the Natural History Museum. In this manner, Joseph Hooker trawled through and inspected an impressive 8000 flowering plants, 7000 of them catalogued by him alone.67 He organised these specimens into genera and families,
taxonomically ‘tidying up’ many thousands of specimens that had been
erroneously classified, or placed in new and unnecessary genera, or were claimed as species when they were simply variants. This was not an easy task by any
64 W.J. Hooker, ‘On the Esculent Plants of Van Diemen's Land’, Companion to the Botanical Magazine… 2, (London, 1836-37), pp. 38-9.
65 J.D. Hooker, ‘On the Huon Pine, and on Microcachrys, a New Genus of Coniferae from Tasmania’, The London Journal of Botany 4 (London, 1845), pp. 137-157. A more thorough examination of the participation of Australian Aborigines in plant collecting for Europeans can be found in P.A. Clarke, Aboriginal Plant Collectors: Botanists and Australian Aboriginal People (Kenthurst NSW, 2008).
66 Hooker, ‘introductory essay’, p. viii. 67 Hooker, ‘introductory essay’, p. iii.
standard, particularly as Hooker had to tread fine lines – he was a taxonomic ‘lumper’ – grouping large numbers of plants together – rather than splitting into minutely differentiated ones. This lumping attitude was one of his most ardently held beliefs, and one that brought him into conflict with some of his colonial collectors.
Examining 7000 plant specimens was no easy task, but it was a luxury that only Hooker could indulge, having such a vast herbarium at his disposal. Hooker needed a large herbarium and within it a manageable number of genera and species, which informed his taxonomic preferences.68 His frequent advice to collectors was to look for intermediate plant forms that would bridge between two similar species, reducing his massive load of specimen sheets. As Endersby discusses, to confer a name upon an object is a powerful act, and there has always been a sense that names can be ‘right’ or ‘wrong’. Centres of power and authority such as Kew were created by the accumulation of specimens, and the holders of these collections would often propose classificatory practices that best suited their own needs.69 Hooker reinforced the Kew principles of classification in the Flora Tasmaniae, and this in turn provided a published model for colonial collectors to follow and aspire to.
The system of classification used by botanists and other biologists is still flexible, although names bend now at the will of appointed committees rather than
68 The power of the herbarium in the relationship between colony and metropole is discussed in Jim Endersby’s ‘“From having no Herbarium.” Local Knowledge versus Metropolitan Expertise: Joseph Hooker’s Australasian Correspondence with William Colenso and Ronald Gunn’, Pacific Science 55 (2001), pp. 343-358.
the personal beliefs of ‘rightness’ held by individuals.70 Currently the Plant Names Project has compiled The International Plant Names Index (IPNI),
maintaining a record of all the vascular plant names in the world.71 Changes to the classification are not uncommon, for example over 27,000 plant names in the index underwent some form of change in 2009. Many of these changes were minor, but major movements do occur.72 Prior to this period of scientific
cooperation and communication regarding the rules of classification, an author’s work could be compromised if his choice of classification system was not in common use by the reading public, as Robert Brown found with his Prodromus.
During the nineteenth century the Linnaean System that grouped plants by the number and position of their stamens and pistils (thus the sexual system), was superseded by Jussieu’s natural system. Linnaean classification had large
deficiencies, often grouping plants together that had only superficial similarities, and separating those which only differed in their sexual organs. The natural system considered the plant as a whole, not just the sexual organs in isolation. The entire flower structure was used as a means of identification. Throughout the nineteenth century the binomials of Linnaeus and the basic structure of Jussieu was the basis for further revision and development.73 As botanical names are authorised by publication, so are additions and changes to systems of
classification. These debates and alterations often surrounded publications on the
70 David Knight has discussed the development and detail of scientific classification systems of the eighteenth and nineteenth centuries in Ordering the World: A History of Classifying Man (London, 1981).
71 IPNI, ‘Mission Statement’, accessed 22 Dec 2009, http://www.ipni.org/mission.html. 72 IPNI, ‘News – Dec 2009’, accessed 22 Dec 2009, http://www.ipni.org/.
Australian vegetation, as it was the plants of this continent that had so challenged previous ideas about the number and variety of global species.
Several of the major publications of the nineteenth century drew upon the Australian flora as a basis for changes to classification systems. Labillardière’s Novae Hollandiae Plantarum Specimen was arranged according to the Linnaean system, and Brown’s 1810 Prodromus was one of the first major works to turn away from the sexual system in favour of the natural. Between 1823 and 1873 Augustin Pyramus de Candolle published his Prodromus Systematis Naturalis Regni Vegetabilis, described by Alex George as ‘one of the greatest botanical works’. De Candolle intended to cover all global flowering plants, but only managed to complete the dicotyledons. His principles were the basis for the International Code of Botanical Nomenclature (ICBN).74 John Lindley was another enthusiastic supporter of the natural system, and publicly stressed this in Britain where the use of the Linnaean system remained into the 1850s. Lindley produced popular works such as Ladies’ Botany that were intended to be easily accessible, whilst simultaneously educating the reader to think according to the natural system. It was the simplicity of the Linnaean sexual system that made it so difficult to shake from the minds of both professionals and amateurs. Even after professionals had agreed that the natural system was far more suitable, texts were still published using the sexual system. It was not until the death of William Hooker in 1865, and Joseph Hooker took over the editorship of the Botanical Magazine that it ceased using the Linnaean system.75
74 Burns and Skemp, VDL Correspondents, p. 14; George, ‘Background to the Flora of Australia’, p. 16.
Following de Candolle, Joseph Hooker, George Bentham and Ferdinand Mueller had the greatest affect upon Australian botanical classification. Hooker’s Botany of the Antarctic Voyage (1855-1860), Hooker and Bentham’s Genera Plantarum (1862-1883), and Bentham’s Flora Australiensis (1863-1878) reinforced the natural system and organised the genera in a manner that became the globally dominant system. This included the introduction of the ‘Kew Rule’, which further strengthened the metropolitan core of botanical classification by controlling the priority of naming species. Bentham argued that commonly used names should stand, regardless of whether they were the first name given. Further, priority was reckoned when a specific epithet was first associated with its ‘true’ generic name, meaning older epithets associated with different genera were ignored.76 This informal law gave Hooker and Bentham even more power in determining naming rights compared to their colonial collectors. They could claim the ‘common’ name was the one they were accustomed to, and not that used by those who lived alongside the plants; and they were the professionals who could reorganise genera and species, with the ability to publish their new classifications.
The Kew Rule has since been abolished, and the ICBN uses the earliest legitimate name, including the earliest species epithet.77 One colonist who fought against the Kew Rule was Ferdinand Mueller. Mueller published prolifically from his base in Melbourne, and worked independently of the great Kew classification schema. His own system was abhorred by Hooker who in a private letter to
Bentham described Mueller as ‘vomiting forth new genera & species with the lack
76 Endersby p. 202; IPNI ‘Understanding the Index Kewensis data’, accessed 23 Dec 2009, http://www.ipni.org/understand_the_data.html.
of judgement of a steam dredging machine.’78 Mueller refused to be controlled by Kew, and all Joseph Hooker could do was smear his name, or ignore him.
In the twentieth century, Australian state floras followed a modified arrangement taken from Mueller, whereas Tasmanian floras continued to follow the Kew model. This included Leonard Rodway’s The Tasmanian Flora of 1903 and Winifred Curtis’s The Student’s Flora of Tasmania from 1956.79 Curtis arrived in Tasmania in 1939 holding an honours degree in botany from University College, London, and experience working at Kew. In her professional life she strongly identified with the Kew classification system, which she instilled in The Student’s Flora. From 1988 the Flora of Australia series has been published following A.J. Cronquist’s system, although like all printed floras it was out of date as soon as it was published.80
As the first volumes of the Flora of Australia were published, new molecular techniques were developed that dramatically altered plant
classification, creating the most significant shifts in plant systematics since the introduction of the natural system. The Angiosperm Phylogeny Group (APG) classification system uses these new groupings to alter plant relationships within families and genera. For example, the genus Archeria (named for William Archer) has moved from the Epacridaceae to the Ericaceae. The division between
78 J.D. Hooker to G. Bentham, Aug 1859, as cited in Endersby, Imperial Nature, p. 201. 79The Student’s Flora was originally devised to update Rodway’s Tasmanian Flora in 1943. Curtis’s work (assisted by fellow botanist Dennis Morris) spanned over forty years and filled five volumes. It remains the foundation text for university students and botanists working on the Tasmanian flora. Unlike the floras that have been published for the other states, The Student’s Flora was designed to be affordable and accessible, stemming from Curtis’s strong teaching background and her need for a solid textbook. Today it stands alone as the only flora of an Australian state or territory that a student can afford. G. Kantvilas, ‘Winifred Mary Curtis: A Biographical Sketch’, in Aspects of Tasmanian Botany: A Tribute to Winifred Curtis, eds. M.R. Banks, S.J. Smith, A.E. Orchard and G. Kantvilas (Hobart, 1991), pp. 1-6.
Dicotyledons and Monocotyledons has become more complex, with some families moving from one group to the other. Other families – in Tasmania the Hydatellaceae – have been revealed to be a sister relation to Angiosperms.81 At present no single classificatory system has become dominant, and it is likely that alterations will only become more frequent. At the core of this quest is the desire to find the ‘truest’ or most ‘natural’ system. Despite advances in science, current taxonomists are, like Linnaeus, Jussieu, and Hooker, aspiring to determine the ‘right’ place and order of organisms.