Page:The Journal of Indian Botany.djvu/364

318 £HE JOURNAL OF INDIAN BOTANY. animals to dense oval bushes (Fig. 13). It is only when the bushes finally spread out so wide that the animals cannot reach the center that shoots spring up into trees. The thorn scrub is destroyed only by cutting combined with cultivation ; cutting alone does not destroy it, for all the species coppice freely, and most of them propagate by shoots from roots. Where cutting is restricted, the Zizyphus jujuba and Acacia arabica develop into a very fair forest (Fig. 15).

As might be expected, there are no bulbous plants, and no epiphytes in the thorn scrub. There are a few lianas, the most com- mon being species of Asclepiadaceae, notably Bemklesmus indicus Br. Where there is more protection, as in planted groves and in hedges around orchards, Cocculus villosus DC, Tinospora cordi/olia Miers. Vitis trifolia L., and a number of Cucurbitaceae are common, but they are unable to survive unrestricted grazing. The parasite, Guscuta rejicxa Roxb., is very common, and whileoccurcing most frequently on Acacia arabica and Zizyphns jicjioba, it is able to grow impartially on almost any available host plant.

Seasonal succession is not such a conspicuous feature of the thorn scrub, though it is well shown in the dry meadow herbaceous vegetation that extends over all such areas. Periodicity is prominent only in leaf fall and in time of blooming. Many of the species are deciduous and have their flowering period during the hot season.

There is little doubt that the meadows of the grass farms and the thorn scrub woody vegetation belong to the same general stage in topographic succession. The former are shrubless and treeless because of the thoroughgoing annual cutting, the wooded areas lack the more advanced grasses because of overgrazing. If left undisturbed, both the protected meadow grasses and the thorny shrubs and trees together would very completely occupy most or all of the area now covered by dry meadows, and would become a dense thorn forest. This actually is happening in the Fisher Forests at Etawah, 200 miles to the west of Allahabad. This is an area along the Jamna Eiver recently placed under Government supervision for afforestation experiments. It is a series of deep ravines developed as the result of the removal of the soil-holding vegetation by overgrazing and unrestricted cutting for fuel. With only five years protection, both the grasses and the woody plants of the thorn scrub stage have developed luxuriently (Fig. 12).

Nowhere over the area about Allahabad has the vegetation been able to develop without protection beyond a poor display of the thorn scrub trees and shrubs, and most of the area is in the dry meadow stage. This stage, so conspicuous under existing conditions, prob- ably would be but a short stage following the wet meadow, or it might even not occur as a distinct stage at all, if the vegetation