AT THE PERIOD OP PUBERTY. 



165 



leaves is purely a protective one, and they are placed in 

 close proximity to the stamens, in order that they may fold 

 over them, and thus shelter them from the falling rain and 

 the dews of night. All must have noticed this folding-up 

 of the calyx and corolla in wet weather, or at sunset. The 

 leaves of the calyx, and especially the petals of the corolla, 

 also aid in the preparation of the sap for the stamens, and 



Fig. 4. 



Longitudinal section of the pistil of Helianthuin denticulafwm, showing 

 the ovules in the interior of the ovary, attached to the placenta by means 

 of the funiculus, or vegetable umbilicus ; 6, style ; c, stigma ; a, pollen 

 granules, the tubes of which have descended the style, and entered the 

 micropyle of the ovules. — Schleiden. 



help to form that saccharine matter which the bee collects 

 so industriously, and which nourishes the stamens and 

 pistils. 



