354 FOUNDATIONS OF BOTANY 



treated with pollen from another flower of the same kind, 

 or cross-pollinated. 1 



424, Wind-Pollinated Flowers. 2 It has already been 

 mentioned that some pollen is dry and powdery, and 

 other kinds are more or less sticky. Pollen of the dusty 

 sort is light, and therefore adapted to be blown about 

 by the wind. Any one who has been much in corn- 

 fields 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. Corn is 

 monoecious, but fertilization is best 

 accomplished by pollen blown from 

 the "tassel" (stamens) of one plant 



FIG. 248.-Pistil of a Grass, b j d t th u ^ , ^ , 



provided with a Feathery 



stigma, adapted for wind- of another plant. This is well 

 shown by the fact, familiar to every 



observing farmer's boy, that solitary cornstalks, such as 

 often grow very luxuriantly in an unused barnyard or 

 similar locality, bear very imperfect ears or none at 

 all. The common ragweed, another monoecious plant, 

 is remarkable for the great quantities of pollen which 

 shake off it on to the shoes or clothes of the passer-by, 

 and it is wind-pollinated. So, too, are the monoecious 

 pines, and these produce so much pollen that it has been 

 mistaken for showers of sulphur, falling often at long dis- 

 tances from the woods where it was produced. The pistil 

 of wind-pollinated flowers is often feathery and thus 

 adapted to catch flying pollen-grains (Fig. 248). Other 



1 On dispersion of pollen see Kerner and Oliver, Vol. II, pp. 129-287. 



2 See Miss NewelFs Botany Reader, Part II, Chapter VII. 



