Sikkim has three types of forests: temperate broad-leaved (1,829-2,730 m), mixed coniferous (2,730-3,650 m), and alpine scrub and grasslands (above 3,650 m). These forests support a wide range of vegetation.

Temperate broad-leaved forests in the state are dominated by oak species like Quercus lineata and Q lamellosa. There are 11 species of oak reported in Sikkim. Other trees include :khrot' (Juglans regia), 'chilounji' (Schima wallichii), cardamom (Cinnamomum obtusifolium) and maple.

Maple (Acer campbellii) trees are also found in mixed coniferous forests, which consist of fir (Abies species), willow (Salix spp.), birch (Betula spp.), 'mahuwa' (Engelhardtia spicata) and, occasionally, the eastern Himalayan larch (Larix griffithiana), spruce (Picea morindoides) and juniper.Species of bamboo and taller varieties of rhododendron are also found in these forests.

Found at altitudes above 10,000 ft, alpine grasslands support a tremendous variety of flora. Plants grow so close together that it is said that with every footstep you trample at least three varieties. In the alpine scrub and grasslands, the common species are 'comari' (Meconopsis spp.), dwarf rhododendron, Rheum species, prostrate juniper (Juniperus prostata), and flowering plants like primula, potentilla, iris, gentian and anemone.