112 INDIAN FOREST MEMOIRS. 



moisture, both on the dry ridges and slopes of the Siwalik Hills and also (rarely) on water- 

 logged soil, and the writer believes that the characters which have been utilised to define 

 these varieties vary in response to the factors of the habitat and particularly in response to 

 the available water supply. 1 Provided that the development of the plants has not bsen 

 interfered with by grazing, grass-cutting, or other agency, those plants with the more hairy 

 glume II are usually less robust and less coarse, or rank, than the others, and they are 

 therefore as a rule most valued for fodder and are distinguished locally by the vernacular 

 name of dhaulu, whereas the coarser plants with smooth glume are called gurla. As this 

 grass affords a valuable fodder and is sometimes cultivated, in consequence, it is important 

 to determine the extent to which its characteristics are constant. If, as suggested above, 

 they depend on the available moisture, it is obvious that cultivation of this grass on good 

 agricultural land, with a large quantity of available moisture, would result in producing an 

 inferior class of rank, coarse fodder. 



The local forms of the species are now being cultivated in the Experimental Garden at 

 Dehra Dun with the object of studying the effect of different soils and varying quantities 

 of available moisture on their characters. 



This will, it is hoped, indicate which forms (if any) of this species are of sufficient im- 

 portance and sufficiently constant to deserve separate definition and description. 



To separately define forms which are connected in the field by numerous intermediates 

 greatly increases the difficulty of identification and is of little practical utility inasmuch 

 as such forms are not likely to remain constant under the ordinary conditions of field-culti- 

 vation. 



C. — Biological and (Ecological Motes. 



Habitat. 93. This plant is in this locality almost in- 



variably found on dry sandy, or stony, soil, with little capacity for holding water. 



It is a frequent associate of A ristida, Triraphis and Saccharum Munja. These plants 

 however are all more vigorous and robust than the present species and Andropogon monti- 

 cola only exceptionally becomes the dominant species under conditions unfavourable for the 

 vigorous development of these stronger competitors. Such conditions are provided by the 

 hot, waterless, and more or less soil-less, ridges and slopes of the Siwaliks, especially on the 

 south of the range, and on deeper moister soil where the stronger competitors are prevented 

 from developing by fire, or other factors. At least one area in the present locality has been 

 seen near Bullawala, where repeated firing has killed out the coarse savannah species Saccha- 

 rum Munja and has resulted in making Andropogon monticola the dominant grass. This 

 would undoubtedly occur more frequently were it not that the burnt grasslands are 

 frequently heavily grazed. 



1 The interesting fact which hus been noted regarding this species that the flowers are much visited by bees naturally suggested that 

 intercrossing might be responsible for intermediate forms and for confusing the boundaries of distinct types, but field study iudicates the 

 available moisture supply as the chief factor affecting the characteristics in question. 



[ H2 ] 



