46 



INDIAN FOREST MEMOIRS. 



For the reasons noted in paragraph 39 above it sis perhaps inadvisable to employ the- 

 terms " old " and " recent alluvium " but Vegetative type III may be said to occur chiefly on 

 what is often known as the high alluvium and Nos. I, II and IV mainly on the low 

 alluvium. Considering the parallel grassland and woodland together as a compound com- 

 munity the above communities may be more briefly defined as below where are also approxi- 

 mately indicated the conditions of soil and moisture, which, in the climate of this locality, 

 enable the various species to here exist together and to form more or less clearly defined 

 communities. 



Community. 



I. Aristida — Acacia 



II. Saccharurn — Dalbergia — Bombax 



III. Saccharurn — Shorea 



IV. Erianthus — Mallotus — Terminalia 



Soil and moisture characteristics of Habitat. 



The soil is very dry ; it consists chiefly of gravel and stones and 

 has very little capacity for retaining moisture or for raising 

 it by capillarity. 



The soil differs from that of No. I in containing a greater 

 proportion of small particles and is therefore more sandy but 

 it is still essentially dry. 



The soil is distinctly loamy and moist, but well aerated and is 

 usually characterised by a more or less considerable ad- 

 mixture of humus. 



The soil is moist to wet, less aerated than that of No. Ill and 

 with a more or less considerable admixture of clay. Owing 

 to the large proportion of clay this soil is apt to become 

 slightly water-logged in the rains and also to suffer from 

 drought after the rains, owing to the capillary movements 

 of water being very sluggish. 



Intermediate 

 Forms. 



42. It must of course be clearly understood 

 that there is no sharp line of distinction between the above communities and just as the 

 factors of the locality, such as the character of the soil, extent of soil aeration, quantity of 

 soil moisture, etc., frequently change very gradually and vary very slightly from place to 

 place, we get habitats with intermediate characteristics and more or less intermediate 

 minor communities connecting the main types. 



Thus considering grassland first, the coarse shingle and gravel thrown up by the most 

 rapidly running currents provide a habitat for the typical desert, or steppe, community 

 composed chiefly of Aristida, with often scattered tufts of Andropogon monticola. As 

 the proportion of small particles increases in the deposits left by less rapidly flowing water, 

 and the soil becomes more sandy, the following species appear; the narrow leaved most 

 xerophilous form of Saccharurn spontaneum, Triraphis, and the narrow leaved, more or 

 less stunted, most xerophilous form of Saccharurn Munja, while Andropogon monticola 

 becomes more vigorous and numerous. As the proportion of sand increases and the capacity 

 of the soil for retaining more moisture and raising it from the water-table by capillarity- 



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