Note 16 — THE ASIATIC STEPPES AND THEIR FAUNA.

[Note 16] p. 91.—Flora of the steppe.

According to Seebohm (op. cit.), “The cause of the treeless condition of the steppes or prairies has given rise to much controversy. My own experience in Siberia convinced me that the forests were rocky, and the steppes covered with a deep layer of loose earth, and I came to the conclusion that on the rocky ground the roots of the trees were able to establish themselves firmly, so as to defy the strongest gales, which tore them up when they were planted in loose soil. Other travellers have formed other opinions. Some suppose that the prairies were once covered with trees, which have been gradually destroyed by fires. Others suggest that the earth on the treeless plains contains too much salt or too little organic matter to be favourable to the growth of trees. No one, so far as I know, has suggested a climatic explanation of the circumstances. Want of drainage may produce a swamp, and the deficiency of rainfall may cause a desert, both conditions being fatal to forest growth, but no one can mistake either of these treeless districts for a steppe or a prairie.” See also for general description of steppe vegetation Kerner’s Plant Life and Wiesner’s Biologic der Pflanzen.