CHAPTER V 

 THE LIFE-HISTORY OF FLOWERING PLANTS 



Whilst flowering plants display a considerable uniformity 

 in their general conduct, they vary amongst themselves in 

 regard to details, such as the duration of their existence, 

 and their precise behaviour during life. Even a single indi- 

 vidual does not acquit itself in a constant and uniform manner 

 throughout life. Its variations in conduct are largely associated 

 with corresponding changes of season. For example, flowering 

 plants in Britain, for the most part, grow actively during summer, 

 but at the onset of winter they tend to enter into a passive or 

 resting condition, during which growth is practically at a stand- 

 still. We can therefore regard the life of a plant as made up of 

 actively vegetating or growing periods and resting periods. 

 Though the British flowering plants commence and conclude 

 their phases of active growth at different times of the year, yet 

 for the vast majority of them the period from spring to autumn 

 is the vegetative season, whilst winter is the resting season. 



FREQUENCY OF FLOWERING AND DURATION OF LIFE. 



Some plants blossom only once in their lives, and die as soon 

 as their seeds have ripened ; they are described as being mo?to- 

 carpic. Opposed to these are others which flower repeatedly 

 and produce crops of flowers year after year : these are termed 

 polycarpic plants. 



Monocarpic plants may be further sub -divided into three 

 groups, according to the age at which they produce their single 

 crop of flowers. A plant which germinates, produces its 

 flowers and fruits, and then dies, all in one vegetative season, 

 is termed an annual — e.g. Wheat and Field Poppy. Some 

 annuals complete this cycle of -Hfe within a few weeks, so that 

 in one vegetative season several generations of individuals may 

 be derived from one plarit : these are small herbs, and are 



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