CHAPTER IX 



^pistil 



FLOWERS 



114. The organs of the flower. Although a brief discussion 

 of the parts of the flower was presented in Chapter II, it will 

 be necessary here to consider them more carefully. Many of 

 the most highly organized flowering plants have flowers with 

 four sets of organs, as shown in figure 101. The outer set 

 (the calyx) consists of parts 

 called sepals, which are usually 

 green and rather leaf -like. Just 

 within or above the calyx comes 

 the corolla, which consists of 

 leaf -like parts (petals) usually 

 of some other color than green. 

 Next comes a set of stamens, 

 which very commonly appear 

 as stalked organs, each with 

 an enlarged, knob-like tip. Fi- 

 nally, the innermost, or upper- 

 most, set of organs consists 

 of carpels, which, if united, constitute the compound pistil, 

 or, if separate from one another, constitute the simple pistils. 



Not many flowers have organs as distinct that is, as 

 wholly separate from each other as they are in the live- 

 forever (fig. 102). In the Hydrophyllum (fig. 101) the organs 

 of each set, except the stamens, appear to be more or less 

 united. The pistil seems to be all of one piece, except that 

 it is two-forked at the tip. Hardly any two kinds of flowers 

 have exactly the same forms and arrangements of the floral 

 organs. A few of the forms are figured in Chapter X. 



126 



FIG. 101. Flower of Hydrophyttum, 

 side view and lengthwise section 



A good example of a flower in which 



the parts of each set except the stamens 



appear to be more or less joined together. 



Modified after Decaisne 



