Raunkiær system

From Wikipedia, the free encyclopedia

The Raunkiær system is a system for categorising plants using "life-form" categories, devised by Christen C. Raunkiær (Raunkiær 1934).

The subdivisions of the Raunkiær system are based on the location of the plant's growth-point (bud) during seasons with adverse conditions (cold seasons, dry seasons):

• Epiphytes — growing upon or attached to another living plant.
• Phanerophytes — projecting into the air on stems - tall, woody or herbaceous perennials with resting buds more than 25cms above soil level, e.g. deciduous trees and shrubs.
• Chamaephytes — at or near the ground - Herbaceous or woody plants with perennating buds borne very close to the ground, no more than 25cms above soil level, e.g. bilberry, periwinkle.
• Hemicryptophytes — resting on the soil surface - plants with resting buds at or near the level of the soil, e.g. daisy, dandelion
• Therophytes — in the form of seeds.
• Cryptophytes — below ground or under water - with resting buds lying either beneath the surface of the ground as a rhizome, bulb, corm, etc., or a resting bud submerged under water.

Cryptophytes are sometimes divided up into:

• Geophytes resting in dry ground, e.g. crocus, tulip.
• Helophytes resting in marshy ground, e.g. reedmace, marsh-marigold.
• Hydrophytes resting by being submerged under water, e.g. water-lily, frogbit.

[edit] Reference

• Raunkiær (1934) The Life Forms of Plants and Statistical Plant Geography published by Oxford University Press.