. Foundations of Botany. Botany. 326 FOUNDATIONS OF BOTANY growths as occur in the rainy forest regions of the tropics. On the other hand, the largest trees on earth, the "big trees," or Sequoias (Fig. 32), occur in the temperate por- tion of North America, along the Sierra Nevada, and the taller, though less bulky, gum trees (Eucalyptus) of Australia grow in a warm temperate region. 398. Temperate Plant Societies due to Special Conditions of Soil. — Even where the climate is a moderate one as regards tem- perature and rainfall, peculiar soils may cause the assemblage of exceptional
. Foundations of Botany. Botany. 326 FOUNDATIONS OF BOTANY growths as occur in the rainy forest regions of the tropics. On the other hand, the largest trees on earth, the "big trees," or Sequoias (Fig. 32), occur in the temperate por- tion of North America, along the Sierra Nevada, and the taller, though less bulky, gum trees (Eucalyptus) of Australia grow in a warm temperate region. 398. Temperate Plant Societies due to Special Conditions of Soil. — Even where the climate is a moderate one as regards tem- perature and rainfall, peculiar soils may cause the assemblage of exceptional plant societies. Some of the most notable of such societies in temperate North America are those of the salt marshes, the sand dunes, and the peat bogs. In salt marshes the water sup- ply is abundant, but plants do not readily absorb salt water by their roots, so that the plants which grow in salt marshes usually have something of the structure and appearance of xerophytes. Some of them are fleshy (Fig. 230), and some species are practically leafless. Sand dunes, whether along the seacoast or near the great lakes, offer a scanty water supply to the roots dur- ing much of the year, and the soil-water contains less of the raw materials for plant food than is offered by that of ordinary soils. Many grasses thrive, however, in these shifting sands (Plate I), and some, like the beach-grass. Fig. 230. — A Halophytic Plant (Salicornia).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bergen, Joseph Y. (Joseph Young), 1851-1917. Boston, Ginn & company
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