Prairie

Prairie [ Ecology - Biogeography ]

Dictionary of botanic terminology - index of names


	A prairie is a relatively flat or gently hilly region in which predominate native grasses and small herbaceous plants with only rare shrubs, and nearly treeless.

It is specifically found in the large plain tract of central North America. Its mesic (moderate or temperate) climate, with light summer precipitations and high summer temperatures is highly favourable for the growth of grass, but there is a considerable risk of drought especially in certain portions, where a semi-arid climate (steppe climate) prevails. Fire is an important part of prairie ecosystem. Grazing by animals also helps to maintain the prairie ecology. The North American prairie is similar, but not completely analogous, to the steppe regions of Europe and Asia and to the Pampas of Argentina.

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Holdfast roots [ Botany ]
Dictionary of botanic terminology - index of names

Some species of climbing plants develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place.

Climbing plants, like the poison ivy (Toxicodendron radicans), Boston ivy (Parthenocissus tricuspidata), and trumpet creeper (Campsis radicans), develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place. Usually the Holdfast roots die at the end of the first season, but in some species they are perennial. In the tropics some of the large climbing plants have hold-fast roots by which they attach themselves, and long, cord-like roots that extend downward through the air and may lengthen and branch for several years until they strike the soil and become absorbent roots.

Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House, 1994