166 



ELEMENTS OF BOTANY. 



205. Protection of Pollen from Unwelcome Visitors. — It is 

 usiTally desirable for the flower to prevent the entrance of 

 small creeping insects, such as ants, which carry little pollen 

 and eat a relatively large amount of it. The means adopted 



to secure this result are 

 many and curious. In 

 some plants, as the com- 

 mon catchfly, there is a 

 sticky ring about the 

 peduncle, some distance 

 below the flowers, and 

 this forms an effectual bar- 

 rier against ants and like 

 insects. Very frequently 

 the calyx-tube is covered 

 with hairs, which are 

 sometimes sticky, as in 

 Fig. 148, I, II, and VII. 

 How these thickets of 

 hairs may appear to a 

 very small insect can per- 

 haps be more easily real- 

 ized by looking at the 

 considerably magnified 

 view of the hairs from 

 the outer surface of 

 mullein petals, shown in 

 Fig. 149.1 



Sometimes the recurved 

 petals or divisions of the 

 corolla stand in the way 

 of creeping insects, as in III and VII. In other cases the 

 throat of the corolla is much narrowed, as in V, or closed 



1 On protection of pollen see Kerner and Oliver, vol. II, pp. 95-109. 



Fig. 148. — Flowers protected from Unwelcome 

 Visitors. 



I, enchanter's nightshade, magnified five times; 

 II, gooseberry, natural size ; III, telliraa, 

 magnified two times ; IV, speedwell, magni- 

 fied four times ; V, bearberry, magnified six 

 times ; VI, hound's-tongue, magnified four 

 times ; VII, nodding campion, natural size, 

 at midnight. 



