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TEXTBOOK OF BOTANY 



unlike a pine cone by a shortening and flattening of its cen- 

 tral axis, so that the spore leaves are borne at nearly the 

 same level, instead of at different levels upon a long axis. 

 The number of spore leaves also is much reduced in the bean 

 flower. 



Another thing that distinguishes it from the pine cone 

 is the presence, outside the spore leaves, of two sets of outer 

 leaves {sepals and petals) which have nothing directly to do 



Fig. 85. — Three views of a bean flower : A , from the top ; B, from the 

 side ; C, also from the side, after the removal of a wing and part of the 

 standard; s, sepals; st, standard; k, keel; w, wing. The stamens and 

 pistil are enclosed in the keel. 



with spore production, but which are none the less impor- 

 tant organs of the flower. Thus a flower, like a cone, is 

 really the end of a stem or branch on which grow certain 

 special leaves, some or all of which bear spores. 



166. Sepals and Petals. — These parts develop before 

 the stamens and pistil, so that the latter are covered and 

 protected in the bud while they are growing. When the 

 stamens and pistil are nearly or quite full growoi, the bud 

 opens — that is, the sepals and petals spread out. The 

 five green sepals, which are the outermost parts of the flower, 

 are united for the greater part of their length into a tube, 

 their free ends projecting as short teeth from the edge of 

 the tube. The petals of some varieties of the bean are 



