MIXED C&OP OP UNIFORM AGE. 47 



two species growing side by side and possessing similarly shaped 

 crowns, but one of which tolerates shade better than the other, the 

 second will ultimately disappear ; whereas a third species, although 

 still less shade-enduring than either, but possessing a differently 

 shaped crown, may be able to occupy a permanent place in the 

 leaf-canopy: 



Lastly, the relative ability of trees to push up through cover has 

 to be considered. Facility for so doing, added to the faculty of 

 persisting under cover, gives a tree possessing it an irresistible 

 superiority over its neighbours. The mariner in which young 

 deodar makes its way up through the dense crowns of overhang-' 

 ing oaks and rhododendrons is an excellent instance in point> 

 There are certain, by their original nature, shade-avoiding trees, 

 which nevertheless, owing to this facility, assume the character of 

 true shade-endurers and are then able to force themselves not only 

 into, but through, the leaf-canopy above. Such species are either 

 comparatively very rapid growers, or, from being in leaf and putting 

 forth new shoots while their companions are entirely out of leaf, are 

 able to spread out, both laterally and upwards, in spite of being over- 

 topped or pressed up against by the crowns of these latter. The 

 most remarkable instance of the first case is that already cited of the 

 Dendrocalamus sir ictus and other bamboos generally, which, al- 

 though extremely partial to light, will shoot up through the lofti- 

 est and deepest cover. Again, the strong leader of the teak will, 

 provided it has not far to go to reach direct sunlight, pierce through 

 the thickest tangled mass of foliage overhead. The second case 

 is best illustrated by the Hanhrlckia binata, young plants of which 

 gradually insinuate themselves through the crowns of the trees 

 immediately above them, especially of khair and, a fortiori, of 

 Boswellia also. Indeed the finest saplings are often those which 

 have grown up in this manner through khair (see Condition XVI 

 infra?) 



V. RELATIVE MASS AND SPREAD OF THE ROOTS (INCLUDING THE 

 RHIZOME). In the heading here a new term has been introduced, 

 t-/~., "relative mass of the roots." In the two preceding Cases. 

 the species in any instance considered being one and the same, al- 

 though the spread of the roots of the various component individuals 

 might differ, still the relative mass or density of the root-system 

 would be the same for all the plants and would be that peculiar to 

 the single species to which they belonged. It is evident that the 

 relative degree of closeness of the roots of a species mu-t influence 

 very considerably its behaviour in the struggle for existence. Thus 



