222 The Golden Rule for Flowers 



river banks. The pistils and stamens of this plant are 

 of three different sizes, but they correspond exactly in 

 height, long pistils with long stamens, short with short, 

 and middle-sized with middle-sized. The long stamens 

 have emerald green pollen, the others yellow ; and the 

 grains vary in size with the length of the stamens, the 

 longer the stamens the larger the grains ; for the 

 larger grains are destined for the longer pistils, and 

 have, of course, to send out longer tubes in order to 

 reach the ovules. 



A bee entering a blossom in search of honey is 

 dusted with pollen on different parts of its body, 

 according to the height of the "stamens, and when it 

 flies off to the blossoms of another plant, if the spots 

 of dust come in contact with pistil-tips of the proper 

 height they may be caught and kept. 



The red Oxalis is another of the plants having 

 pistils and stamens of three sizes, and a large field in 

 Brazil containing many acres of this plant yielded not 

 a single seed, because, though pollen and insects were 

 both plentiful, all the plants chanced to be of the same 

 ' form,' as it is called : all had long pistils and short 

 stamens, or vice versa, and the pollen was of no use. 

 Other plants possess similar peculiarities, but we will 

 mention one which all can examine for themselves 

 the common yellow primrose. 



The blossom of the primrose is a long tube flattened 

 out at the top into five divisions. If we look at a 

 bunch of primroses gathered from different plants, we 

 see at once that all are not alike. In some the pistil, 

 with a knob like a pin's head, stands up just out of the 

 tube; in others no pistil is visible, but in its place, 



