Friday, December 07, 2007

Survivors in a tough world

Plants that grow in the frozen land north of Brooks Range must have special qualities to survive the cold, wind and low rainfall. All plants grow close to the ground, minimising the battering effects of cold. desiccating winds - the polar willow (Salix polaris), for example, grows flat on the ground. Heat is trapped in clumped plants - the temperature in the centre of a clump of moss campion may 22 degree C (40 degree F) higher than the surrounding air. Moss campion's narrow leaves cut down moisture loss, and so do leaves pressed close to a stem, such as the arctic bell heather's. Only at flowering time do stems reach above the tundra carpet, and then they bend in the wind.

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