Life Forms - Qualitative Characters
The form and structure of terrestrial communities are determined by the nature of vegetation. Vegetation may be classified according to growth form. The plants may be tall or short, herbaceous or woody, evergreen or deciduous. We might speak of trees, shrubs, and herbs, and then further sub-divide these categories into needle-leaved evergreens, broad-leaved evergreens, broad-leaved deciduous, shrubs, ferns, grasses and so on and so forth.
A more useful system was proposed by a Danish botanist, Christen Raunkiaer in the year 1903. In this system, instead of considering plants' growth form, he classified plants by life form, the relation of their height above ground to their perennating organ. A perennating organ is one that survives from one growth season to the next, remaining inactive over winter or dry periods. Perennating tissue is the embryonic or meristematic tissue of buds, bulbs, tubers, roots and seeds.