Raunkiaer system

Method of classification devised by the Danish ecologist Christen Raunkiaer (1860–1938) whereby plants are divided into groups according to the position of their perennating (overwintering) buds in relation to the soil surface. For example, plants in cold areas, such as the tundra, generally have their buds protected below ground, whereas in hot, tropical areas they are above ground and freely exposed. This scheme is useful for comparing vegetation types in different parts of the world.

The main divisions are phanerophytes with buds situated well above the ground; chamaephytes with buds borne within 25 cm/10 in of the soil surface; hemicryptophytes with buds at or immediately below the soil surface; and cryptophytes with their buds either beneath the soil (geophyte) or below water (hydrophyte).