ECOLOGY OF FLOWERS; POLLINATION 169 



wind. Any one who has been much in cornfields after 

 the corn has " tasseled " has noticed the pale yellow dusty 

 pollen which flies about when a cornstalk is jostled, and 

 which collects in considerable quantities on the blades of 

 the leaves. C!om is monoecious, but fertilization is best 

 accomplished by pollen blown from the " tassel " (stamens) 

 of one plant to the " silk " (pistils) of another plant. The 

 pistil of wind-pollinated flowers is often feathery and thus 

 adapted to catch flying pollen- 

 grains (Fig. 125). Other charac- 

 teristics of such flowers are the 

 inconspicuous character of their 

 perianth, which is usually green fig. 125. PistU of a Grass, 

 or greenish, the absence of odor provided with a Feathery 

 and of nectar, the regularity of Stigma, adapted for Wind- 



=> " •' Pollination, 



the corolla, and the appearance 



of the flowers before the leaves or their occurrence on 

 stalks raised above the leaves. 



Pollen is, in the case of a few aquatic plants, carried 

 from flower to flower by the water on which it floats. 



199. Insect-Pollinated Flowers. — ]\Iost plants which 

 require cross-pollination depend upon insects as pollen- 

 carriers,-' and it may be stated as a general fact that the 

 showy colors and markings of flowers and their odors all 

 serve as so many advertisements of the nectar (commonly 

 but wrongly called honey) or of the nourishing pollen 

 which the flower has to offer to insect visitors. 



200. Pollen-Carrying Apparatus of Insects.^ — Ants and 

 some beetles which visit flowers have smooth bodies to 

 which little pollen adheres, so that their visits are often of 



1 A few are pollinated by snails ; many more by humming-birds and other 

 birds. 2 See Knuth-Davis' Handbook of Floii-er Pollination. 



