HOLE : SOME INDIAN GRASSES AND THEIR CECOLOGY. 123 



Examples of the second are Kanswala Tappar and parts of Palasi Tappar in Lachi- 

 wala Range. 



Grasslands of the first class appear to owe their characteristics mainly to the fact that 

 they are surrounded on all sides by dense forest, on account of which free circulation of air 

 is impossible. These areas are therefore subjected to intense heat by solar radiation during 

 the day and hot season and to great cold by terrestrial radiation during the night and cold 

 season. The natural result of these influences is to diminish the water-content of the soil 

 and to cause great damage from frost, i.e. to create conditions only suitable for the develop- 

 ment of xerophilous, or the less mesophilous, and frost-hardy species. 



101. On the loamy soil prevailing in Zabar- 

 khet, which is fire-protected, the grass which should be dominant is the coarse mesophilous 

 Saccharum Narenga. The latter, however, is here seen to grow vigorously, as a rule, only 

 near the edges of the grassland where the shade of the surrounding forest keeps the soil 

 moist, while, in the most exposed portions of the area, the far less mesophilous Androfogon 

 intermedins tends to become dominant. 



In Gola Tappar which is regularly fired, but which lies higher and where there is 

 possibly more air circulation, the drying action is intensified by fire and here again 

 Saccharum Narenga is seen to be of inferior vigour and dimensions. Here, however, pro- 

 bably on account of its fire-hardy fruiting spikelets, Androfogon contortus to a consider- 

 able extent takes the place of A ndropogon intermedins. 



Grasslands of this type appear, as a rule, to have been caused by clearings which were 

 made in the forest for the purposes of cultivation and then abandoned. 



In those grasslands where, owing to the small size or shape of the area cleared, or to 

 the configuration of the ground, a certain amount of shade is derived from the surrounding 

 forest, or where a few trees were left scattered over the area at the time of clearing, the 

 effect of such shade in increasing the water content of the soil is very marked. As 

 already noted above, Saccharum Narenga is vigorous near the edges of Zabarkhet, while a 

 walk through Gola Tappar only showed a single vigorous plant of the moisture-loving 

 Erianthus Ravenna^ which was situated beneath the ample shade of a large tree of Ficus 

 bengalensis. This prevalence and increased vigour of strongly mesophilous grasses in 

 these areas near the shade of trees is very marked, has been frequently noticed, and is a 

 very striking illustration of the value of shade under these conditions in the way of increas- 

 ing the water content of the soil. 



102. As regards the question of frost, it 

 should first be noted that low temperature is believed to be injurious to woody plants in two 

 principal ways : — 



(a) Indirectly by desiccation. When the soil temperature falls below a certain point 

 the roots are no longer able to absorb the necessarv supplies of water. While 



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