Kirstenbosch National Botanical Garden Trip Planning

By 1980 the rate of new specimens accessioned at the National Herbarium, Pretoria, reached a peak of 18 000 per year, reflecting the local enthusiasm for botanical collecting. Of concern is that, by 2010, the number of new accessions had dropped to 2 000 per year, a level last recorded in 1905. The transfer of energies from taxonomy to ecology has much to do with this, but an underlying cause of the demise of field collecting is the increasing weight of bureaucracy and legislation attending the simple practice of biodiversity inventory. The United Nations Convention on Biodiversity (CBD), for all its impressive outcomes, is victim of the unintended consequences of its policies on the control of access to biological material. Legislation has now so constrained collecting activities that the CBD might soon be recognised as the ‘dead hand on biodiscovery’.

Kirstenbosch National Botanical Garden Trip Planning Photo Gallery

Taxonomy – the science of classifying and naming organisms Until 1753, plants and animals were collected, preserved and described using long and often confusing, or difficult-to-catalogue, names – and all this in Latin, the universal language of the day.

By the early 18th century, plant and animal collections resulting from the exploration of Africa, Asia and the Americas were burgeoning, and there was an urgent need for an efficient and consistent system of classifying and naming the thousands of new specimens arriving in the museums, herbaria and universities of Europe. The science of classifying and naming organisms, known as taxonomy, was born. Taxonomy includes four components – classification; naming (nomenclature); the circumscription and description of species, genera, families, etc; and the production of identification tools. Closely related is the science of systematics, the study of the diversity of organisms and the relationships among them, which includes elements of evolution, phylogeny, population genetics and biogeography. Today the lines between taxonomy and systematics have merged as the implementation of molecular technologies has called for a greater synthesis of approaches.

Carolus Linnaeus The father of modern taxonomy: Swedish naturalist Carolus Linnaeus (1707-1778) The father of modern taxonomy was the Swedish naturalist Carolus Linnaeus (1707-1778). Linnaeus revolutionised plant taxonomy with his so-called ‘sexual system’, based on the number and arrangement of the reproductive organs, the stamens and pistils. Linnaeus created a large number of genera and assigned each species to a genus. Today, taxonomists group genera into families, families into orders, orders into classes and classes into divisions within the Plant Kingdom

It is certainly thanks to the great Linnaeus that we have an orderly arrangement of our knowledge of global biodiversity. Few words can better express an appreciation for the Cape’s flora, than those in a letter from Linnaeus to Governor Tulbagh written in the mid-18th century:

‘May you be fully aware of your fortunate lot in being permitted by the Supreme Disposer of events to inhabit, but also enjoy the sovereign control of that Paradise on Earth, the Cape of Good Hope, which the Beneficent Creator has enriched with His choicest wonders. Certainly if I were at liberty to change my fortune for that of Alexander the Great, or of Solomon, Croesus or Tulbagh, I should without hesitation prefer the latter. ’

A ‘species’ is the most fundamental level of classification – it is the building block of any analysis of biodiversity. In its simplest definition, members of a species can interbreed with one another, but not with other species. Next up the hierarchy of taxonomy is the genus – a grouping of similar, closely related species. The genus is a somewhat subjective category, leading to much debate among taxonomists and to confusion for those foreign to the arcane principles of taxonomy, or to the bizarre International Code of Botanical Nomenclature. Essentially, a genus is the ensemble of its component species and, likewise, a plant family is the ensemble of its component genera.

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