148 



PLANT BIOLOGY 



irregular and provided with nectar and strong perfume are 



usually pollinated by insects. Gaudy colors probably attract 



insects in many cases, but perfume appears to be a greater 

 attraction. 



The insect visits the flower for the 

 nectar (for the making of honey) and 

 may unknowingly carry the pollen. 

 Spurs and sacs in the flower are necta- 

 ries (Fig. 200), but in spurless flowers 

 the nectar is usually secreted in the 

 bottom of the flower cup. This compels 

 the insect to pass by the anther and 



FIG. 200. FLOWER OF rub against the pollen before it reaches 

 LARKSPUR. ^ nectar Sometimes the anther is a 



long lever poised on the middle point and the insect 



bumps against one end and lifts 



it, thus bringing the other end 



of the lever with the pollen sacs 



down on its back. Flowers that 



are pollinated by insects are said 



to be entomophilous (" insect lov- 

 ing"). Fig. 200 shows a 'larkspur. 



The envelopes are separated in 



Fig. 20 1. The long spur at once 



suggests insect pollination. The 



spur is a sepal. Two hollow 



petals project into this spur, ap- 

 parently serving to guide the 



bee's tongue. The two smaller 



petals, in front, are peculiarly 



colored and perhaps serve the bee in locating the nectary. 



The stamens ensheath the pistils (Fig. 202). As the insect 



stands on the flower and thrusts its head into the center, 



FIG. 201. ENVELOPES OF A 

 LARKSPUR. There are five 

 wide sepals, the upper one be- 

 ing spurred. There are four 

 small petals. 



