112 BIOLOGY FOR BEGINNERS 



visitors are kept out by hairy or sticky coatings on stem and 

 calyx or on the inside of the corolla. 

 Essential Organs. Notice that the only organs absolutely needed 



FIG. 35. Spartium, showing the dusting of the pollen through the opening 

 keels on the under side of an insect. (From Kerner and Oliver, see Kellogg.) 



to produce seeds are the stamens and pistil. Hence they are called 

 the " essential organs." The corolla and calyx have, as their 

 function, the protection of these essential organs and the securing 

 of pollenation. 



