370 



ELEMENTS OF GENERAL SCIENCE 



(fig. 171) is the reproductive organ in seed plants. It con- 

 sists of four distinctly different kinds of structures, some of 

 which may be absent. In a complete flower the lowest floral 



organs are the 

 sepals (fig. 172), 

 collectively known 

 as the calyx; next 

 above the sepals 

 are the petals, col- 

 lectively known as 

 the corolla; above 

 the petals are the 

 stamens; and above 

 the stamens are 

 the pistils. In the 

 flowers of some 

 plants the pistils 

 are absent and the 

 flowers are pistil- 

 late. Sometimes 

 pistillate flowers 

 are borne on some 

 of the branches of 

 a plant, and stami- 

 nate flowers on 

 other branches. 



380. The pistil. 

 Careful observation 

 of the pistil will or- 

 dinarily show that 

 there is a swollen basal portion known as the ovary, above 

 which is a more elongated part, the style, and above that the 

 tip portion, known as the stigma. By opening the ovary we 

 may find within it small bodies, the ovules (fig. 173), which 

 when mature are the seeds. When we take a very thin section 



FIG. 171. Flower of ainaryllis 



The sepals and petals are almost identical in shape and 

 color. There are six stamens and one pistil in each flower 



