(Magor 1990), and referred to as Chamaerhododendron (low-growing rose tree), the genus was first formally described by Linnaeus in his Species Plantarum in 1753. He listed five species under Rhododendron (Rhododendron ferrugineum (type species), R. dauricum, R. hirsutum, R. chamaecistus (now Rhodothamnus chamaecistus (L.) Rchb.) and R. maximum). At that time he considered the then known six species of Azalea that he had described earlier in 1735 in his Systema Naturae as a separate genus. Linnaeus' six species of Azalea were Azalea indica, A. pontica, A. lutea, A. viscosa, A. lapponica and A. procumbens (now Kalmia procumbens), which he distinguished from Rhododendron by having five stamens, as opposed to ten. As new species of what are now considered Rhododendron were discovered, they were assigned to separate genera if they seemed to differ significantly from the type species. For instance Rhodora (Linnaeus 1763) for Rhododendron canadense, Vireya (Blume 1826) and Hymenanthes (Blume 1826) for Rhododendron metternichii, now R. degronianum. Meanwhile, other botanists such as Salisbury (1796) and Tate (1831) began to question the distinction between Azalea and Rhododendron, and finally in 1836, Azalea was incorporated into Rhododendron and the genus divided into eight sections. Of these Tsutsutsi (Tsutsusi), Pentanthera, Pogonanthum, Ponticum and Rhodora are still used, the other sections being Lepipherum, Booram, and Chamaecistus. This structure largely survived till recently (2004), following which the development of molecular phylogeny led to major re-examinations of traditional morphological classifications, although other authors such as Candolle, who described six sections, used slightly different numeration. Soon, as more species became available in the nineteenth century so did a better understanding of the characteristics necessary for the major divisions. Chief amongst these were Maximovicz's Rhododendreae Asiae Orientali and Planchon. Maximovicz used flower bud position and its relationship with leaf buds to create eight "Sections". Bentham and Hooker used a similar scheme, but called the divisions "Series". It was not until 1893 that Koehne appreciated the significance of scaling and hence the separation of lepidote and elepidote species. The large number of species that were available by the early twentieth century prompted a new approach when Balfour introduced the concept of grouping species into series. The Species of Rhododendron referred to this series concept as the Balfourian system. That system continued up to modern times in Davidian's four volume The Rhododendron Species. Modern era The next major attempt at classification was by Sleumer who from 1934 began incorporating