THE FLOWEH 



247 



of the partridge berry, and the recurved edges of corollas 

 like those of the morning-glory and tobacco, over which small 

 crawling insects cannot easily climb. 



Of flowers that are pollinated by night moths, some close 

 during the day, as the four-o'clock and the evening primrose ; 

 and vice versa, the morning-glory, dandelion, and dayflower 

 (Commelyna) unfold their beauties only in the sunlight. 

 For similar reasons, night-blooming flowers are generally 

 white or very light-colored, and shed their fragrance only after 

 sunset. A nodding position is assumed by many flowers at 

 night, or during a 

 shower, to keep the 

 pollen from being 

 injured by dew or 

 rain. 



281. Insect depre- 

 dators. The secre- 

 tion of honey by 

 flowers is a very 

 common means of 

 attracting insect visitors, and various adaptations, such as 

 spurs, sacs, and pockets, are found for protecting it against 



pillage by unwelcome in- 

 truders. In general, plants 

 that have very long, tubular 

 FiG.366.-Headoftheswordbiiuhird corollas, like the trumpet 



adapted to feeding on nectar from long, honeysuckle (LoUlCem Sem- 

 tubular corollas. . x . , 



permrens) and the trumpet 



vine, are reserving their sweets for humming birds and long- 

 tongued moths and butterflies. This protective arrange- 

 ment is not always successful, however, against insect depre- 

 dators, for it is not uncommon to find such corollas with a 

 hole in the tube near the base, made by thieving wasps and 

 bumblebees, which by this means get at the honey without 

 paying their due tribute of pollen. 



FIG. 364. A flower of the trumpet vine (Tecoma 

 radicans) adapted to pollination by humming birds 

 and humming bird moths, which has been pierced by 

 bees or wasps for honey. 



