66 THE STRUGGLE FOB EXISTENCE. 



their, final change into ripe fruit ; and the liability to failure from 



those causes will of course be proportionate to the length of this 



interval. Thus between the appearance of the flower bud and the 



maturation of the cone of the deodar more than a whole year 



elapses, with the consequence, in the severe climate affected by that 



species, that seed forms on an average in only one year out of every 



three. Similarly, teak near its northern limit in India, although, 



thanks to the genial temperature during the rainy season, it flowers 



abundantly every year, not seldom fails to form fruit owing to 



the heavy frosts of December and January. And so with Termi- 



nalia tomentosa, &o. On the other hand, the entire activity of the 



inflorescence bud of sal is accomplished between March and the 



following June, so that, unless fires are so exceptionally severe as to 



scorch up every green thing in the crowns of the trees, or insects 



are exceptionally numerous and destructive, a certain quantity of 



seed must be produced every year. 



Some species, like the ffardioickia binata for instance, produce 

 flower buds generally, or only, in very dry years. Drought has 

 also, no doubt, some influence on the flowering of bamboos, which 

 frequently coincides with, or immediately follows, years of scarcity. 

 And, indeed, drought may generally b.e said to favour the produc- 

 tion of flower-buds by weakening and diminishing the foliage of 

 the trees, and thus giving a fillip to sexual activity. 



Frequency of seeding is also dependent on the degree of densi- 

 ty of the leaf-canopy, some trees, as already stated under (a), re- 

 quiring a smaller measure of isolation than others to produce 

 flowers and fruit. For instance, it is a matter of common experi-. 

 ence in Assam to find isolated individuals of Afewa ferrea loaded 

 with fruit, while the seed-collector wastes his pains in canopied 

 masses of that species. The same is strikingly the case with 

 deodar and the firs in the N. W. Himalayas, 



And generally it may be said that whatever extraneous condi- 

 tions favour profuseness, also favour frequency of seeding. 



(c) Size and transportability of the s.eed. Large and heavy 

 seeJs, like acorns, will drop almost vertically on the ground, while 

 the minute seeds of Step/irr/i/ne, Adina, Pieris, &c. will be blown 

 away to considerable distances by the slightest breeze. But large 

 a:id heavy seeils also may, thanks to winglike or hairy appendages, 

 such as are found in teak, sal, Pterocarpus Marsupium, Termina- 

 l',i tomentosa, &c., be wafted away some distance from the parent 

 tree by wind. When small or light seeds are armed with such ap- 

 pendages, they may be blown away for miles ; e. g. seeds of many 



