<P> Although meticulous, the classification of Linnaeus served merely as an identification manual; it was based on phenetics and did not regard evolutionary relationships among species . It assumed that plant species were given by God and that what remained for humans was to recognise them and use them (a Christian reformulation of the scala naturae or Great Chain of Being). Linnaeus was quite aware that the arrangement of species in the Species Plantarum was not a natural system, i.e. did not express relationships . However he did present some ideas of plant relationships elsewhere . </P> <P> Significant contributions to plant classification came from de Jussieu (inspired by the work of Adanson) in 1789 and the early nineteenth century saw the start of work by de Candolle, culminating in the Prodromus . </P> <P> A major influence on plant systematics was the theory of evolution (Charles Darwin published Origin of Species in 1859), resulting in the aim to group plants by their phylogenetic relationships . To this was added the interest in plant anatomy, aided by the use of the light microscope and the rise of chemistry, allowing the analysis of secondary metabolites . </P> <P> Currently, the strict use of epithets in botany, although regulated by international codes, is considered unpractical and outdated . The very notion of species, the fundamental classification unit, is often up to subjective intuition and thus cannot be well defined . As a result, estimate of the total number of existing "species" (ranging from 2 million to 100 million) becomes a matter of preference . </P>

The nomenclature scheme applied to around 6000 plants in 1753 was created by