ioo MINUTE MARVELS OF NATURE 



group as the evening primrose. Indeed, it is, 

 generally speaking, an easy matter for the botanist 



Fig. 63. A portion of the stigma of the evening primrose shown 

 in section with the pollen-grains emitting pollen-tubes which 

 penetrate the tissues of the stigma and ovary 



to trace the family to which a plant belongs by 

 examination of the pollen-dust alone ; for the 

 grains usually possess characteristic features, 



