INTRODUCTION 45 



from the centre. The number and the form of the 

 stamens is a matter of interest, and served Linnaeus, 

 in the case of their number, as a basis for his system 

 of arrangement. The position of the stamens in 

 relation to the receptacle or the ovary is important in 

 a natural system of classification. The stamens may 

 be united as in Leguminosse, entirely so, or all but 

 one may be united. They may be divided into two 

 groups, long and short. Their arrangement in 

 relation to the honey is important. The amount of 

 pollen (and stamens) varies with the mode of polli- 

 nation. In wind-pollinated flowers the pollen is 

 more abundant and the stamens more numerous than 

 in a typical insect-pollinated flower. The size of the 

 pollen-grains varies, so do their form and surface 

 characters. All these and many other points form 

 interesting phases of each plant's life-history. 



As has been said, the carpels or pistil are usually 

 in the centre of the bisexual flower. 



The pistil consists of an ovary, with one or more 

 ovules within, with a style and stigma above. The 

 position of the ovary in relation to the perianth is a 

 matter of importance. So is the adherence or non- 

 adherence of the ovary to the other parts of the 

 flower. The ovary is sometimes free or apocarpous, 

 as in RanunctduSy etc. 



The number of chambers in the ovary may be few 

 or many, as many as the carpels or not. The 

 ovary may vary in its shape, as may the ovules. 



As in the case of the stamens the mode of poUina- 



