REPRODUCTION OF OFFSPRING 13 



Alpine plants special protections in connection with 

 these organs, in order to guard against excessive 

 transpiration. 



Such briefly are the vital functions which the 

 plant has to perform to fulfil its duty to itself — the 

 maintenance of its own existence. We shall find that 

 many of the peculiarities of Alpine plants are to be 

 explained as special adaptations, in order to ensure 

 that these functions shall not be interfered with by 

 the influence of the severe climatic conditions, which 

 the plant has to face. Unless we have some com- 

 prehension of the vital processes of Alpine plants, 

 we shall naturally not possess the key to an 

 understanding of many of the peculiarities of habit 

 which they present, and thus it has seemed well to 

 enter here, at the outset, into these matters somewhat 

 at length. 



The plant has also a second duty : the production 

 of offspring. The means by which this is effected 

 are more generally understood, and need only a passing 

 reference here. In the plants which stand highest of 

 all in a botanical sense, the Flowering Plants (Angio- 

 sperms), with which we are here alone concerned, the 

 essential features of the flowers, are as follows. 



The male organs — stamens — produce the pollen 

 grains, which in turn furnish sperms, which fertilise 

 the eggs contained in the ovules. The ovules are 

 borne by and enclosed in modified leaves termed 

 carpels. Both the male and female organs may be 

 found in the same flower, or in separate unisexual 



