110 PLANT-LIFE ON LAND [CH. 



stage. Clearly the shorter that time, other things 

 being equal, the greater will be the propagative power 

 of the species. The annual plant germinates, de- 

 velopes, fructifies, and dies all in a single season. 

 Sometimes in arctic or alpine regions (which, however, 

 are on that account little suited to the life of annuals) 

 that season may be only a few weeks in duration. On 

 the other hand, many plants live and grow for a long 

 term of years merely as vegetative individuals, enter- 

 ing late upon a propagative period. In some cases, 

 as the gigantic Talipot Palm (Corypha\ or many Bam- 

 boos, the parent plant then dies. In other cases, as in 

 many forest trees, the fructification may be repeated 

 annually. In others again, as in the Common Beech, 

 a period of storage of nutriment may extend over a 

 series of years, to be terminated by a profuse fructi- 

 fication which suddenly depletes the store. Such 

 differences of behaviour modify, it is true, the details 

 of the propagative output, but the rate of increase is 

 as a rule so great that their effect is apt to be 

 swamped in the vastness of the totals, when taken 

 over an average of years. 



In considering the chances of any given germ 

 becoming established as a new individual, the amount 

 of nutriment which it carries with it is a matter of 

 the highest moment. The larger the supply the more 

 thoroughly can the germ fit itself for acquiring its 

 own sustenance before the need for doing so actually 



