102 GREOAKIOUSNESS AND SOCIABILITY OF SPECIES. 



and the first of them occurring while all, or nearly all, its neigh- 

 bours are leafless. 



(A) The number and extraordinary vigour of the collum buds 

 in the young seedling. 



(/) The great hardihood of the young plant even without the 

 help of the collum buds. 



(j) The surprising ability of the young plant, thanks to cha- 

 racter (y), to withstand the lowest and densest cover of its usual 

 companions, and, with its thin flexible leading shoot, to work its 

 way up through the overhanging crowns of those species. Also 

 see p. 80. 



(/if) The extraordinary power enjoyed by the species of recov- 

 ering from the severest mutilation, including injury by fire. 



(/) The very much greater height attained by it in comparison 

 with most of its companions. 



(m) Its very rapid gro\vth as soon as it is established. 



() Its generally superior longevity. 



In the immediately preceding examples we have limited our- 

 selves to showing, without entering into any lengthy explanatory 

 details, why the species selected for illustration are gregarious. 

 The reasons given are sufficiently obvious after the general dis- 

 cussion of the Straggle for Existence in Chapter II. In the fol- 

 lowing paragraphs we will continue the application of the princi- 

 ples therein exposed and demonstrate, by means of the example of 

 teak and Prosopis spicigem, how one and the same species may be 

 gregarious or exclusive under certain circumstances and sporadic 

 or sociable under others. 



Teak where gregarious. 



Over the wide area of Central India teak is gregarious either 

 (A) on alluvial flats along the courses of rivers, or (B) on small 

 stretches of stiflish sandy soil once under squatter cultivation, or 

 (C) on hillsides, flats, or stretches of undulating ground, which 

 have for centuries been subjected to the dliaya system of cultiva- 

 tion already described on page 24. 



A. The soil in the alluvial flats referred to is more or less saline, 

 with a strong admixture of carbonate and sulphate of lime, and is, 

 in many instances, submerged for a few days every year during 

 the floods of the rivers. It becomes, on the other hand, extremely 

 dry and hard for several feet below the surface, when the rivers 

 have subsided into their normal beds during the hot weather. 



