Page:The Journal of Indian Botany.djvu/356

310 cate branches die. The hard resistent parts remain alive, and continue to put out a few new leaves and bloom profusely throughout this season. The herbaceous vegetation is characterized by well developed perennating organs. Prostrate and rosette forms abound. Much of the soil surface is exposed, and a pall of impalpable grey dust settles over everything. Both in aspect and structure the vegetation is distinctly xerophytic.

The vegetation of the cold season is more representative than at any other time of the year. Besides the many plants peculiar to this season, some of the more hardy of the rainy season annuals persist, and the vegetation exhibits a freshness and vigor that is lacking in the hot season. The outstanding features of succession are also more obvious at this time.

The influence of man on the vegetation. It is impossible to determine what was the condition of the vegetation in the Upper Gangetic Plain before the interference of man. Doubtless many plants have been directly exterminated, and others have been killed by removal of some sort of protecting forest cover; others have been eliminated in competition with plants introduced along with man, and by the changed conditions resulting from his various activities. But man has been present long enough, and has maintained his conditions of living sufficiently unchanged that the vegetation has become balanced against him. With the awakening in agriculture, the human factors are beginning to change, and in consequence we may expect more or less profound changes to take place in the vegetation again. The effect of the human factors is to interfere with the natural development of the vegetation, and to throw it back to a more primitive stage. If the human factors about Allahabad where to become much more intense, there would result the extinction of many valuable native plants, and a further regression in the vegetation; if the human factors where to relax in intensity, the vegetation would at once pass on to a more advanced stage; if man were removed entirely the vegetation would ultimately reach a climatic climax, though different in detail from the one present when man first arrived on the scene in significant numbers. This balance between the progressive tendencies of the vegetation and the retrogressive influence of man is one of the most striking features of the local vegetation.

Not only has man caused the vegetation to retrogress from the original climax, and is now in a state of balance with it, but he interferes with normal succession in edaphic areas so profoundly that it may actually be prevented. Pools, for example, that should show early stages in succession, serve as bathing places for man and beast.