Nepal's monsoon climate and huge altitudinal range create a wide array of habitats, from the lowland evergreen tropical forests in the Terai (below 200m), through warm temperate evergreen, cool temperate deciduous forests and then coniferous forest to the tree line. Above this Rhododendron scrubland extends up to the high alpine meadows before plant life gives way to the frozen wastes of the barren snow capped peaks of the world’s highest mountains (the highest recorded flowering plants are found at around 6100 m). The deep river valleys create their own microclimates, and dramatic changes in the vegetation can be seen in relatively small areas with differing aspect and altitude.Schweinfurth (1957) produced the first vegetation map of the entire Himalaya, and laid the foundations for more detailed work in Nepal by later authors. Stearn (1960) proposed a broad catagorisation of Nepal into three geographic regions: Western Nepal (west of the Karnali River, ca. longitude 83°E), dominated by a western Himalayan flora; Eastern Nepal (east of the Koshi River, ca. 86°30'E), dominated by an eastern Himalayan flora; and Central Nepal (between 83° and 86°30'E), comprising a mixing zone of these two floras. This did not distinguish any altitudinal differences, but was used as the basis for the first comprehensive checklist of the plants of Nepal (Enumeration of the Flowering Plants of Nepal, Hara et al., 1978 et seq.). In contrast zoologists Swan and Leviton (1962) used a system of seven ecological zones based on altitude, but did not differentiate any east-west patterns.Two landmark publicatons appeared in 1972, both the result of many years of fieldwork by the authors, combined climatic and phytogeographic regions. These two systems of vegetation classification (Stainton, 1972 and Dobremez, 1972) are widely used today and are outlined below. Other notable contributions to plant ecology and vegetation studies in Nepal have been made by George Meihe (and co workers, 1990 onwards) and Shakya et al. (1997). It should be noted that in all these systems generalisations need to be made as vegetation zones are greatly affected by local conditions, particularly rainfall and aspect. Sometimes the boundaries are abrupt and clear, but often they are gradual and intergrade over quite large areas. The vegetation pattern for the whole country is a complex mosaic and the categorisation is still open to debate.