240 



BOTANY FOR BEGINNERS 



CHAP. 



ion of 



seed, the production of the seedling, and its growth until 

 maturity is reached. Flowering then takes place, once or many 

 times, and seeds are formed. The plant may only live a few 

 years, or for a thousand years. It is a common thing to see 



trees with several hun- 

 dred rings, which mark 

 so many years of growth, 

 and a section of the 

 Sequoia in the British 

 Museum has 1330 annual 

 rings. The life-history of 

 such a plant is shown in a 

 graphic manner in Fig. 

 'Material 



Growth 



236. 



SUMMARY. 



FIG. 235. Graphic illustration of the Life- 

 history of a biennial plant. 



The Necessity for Eepro- 

 duction is shown by the 

 death of the individual 

 plant. It is only by new 



plants being produced that it is possible for a race of plants to con- 

 tinue. There are two ways by which new individuals can be pro- 

 duced-^) by vegetative re- Germination of 

 production ; (b) by sexual 

 reproduction. 



Vegetative Reproduction 

 of a plant takes place by a 

 portion of the vegetative part 

 of the plant being severed 

 from the parent ; this leads 

 an independent life as a new 

 individual. 



The Sexual Reproduction 

 of a plant is brought about 

 by the union of two cells ; 

 these by their union produce 

 one cell which develops into 

 the embryo. 



The Biological import- 

 ance of Reproduction is 

 shown in the multiplication 

 of the individual, and by the better chance it gives the offspring by the 

 distribution of the seeds far away from the parent. The seeds pro- 

 duced can stand extremes of climate better than the mature plant. 



The Life-History of a plant consists of all the changes which it under- 

 goes from birth to death. 



FIG. 236. Graphic illustration of the Life- 

 history of a perennial plant. 



