TRITICUM 



93 



sterile. In Fig. 28, the lemmas of four flowers are visible. 

 As a rule, but two grains mature. In some varieties, most 

 of the spikelets mature three grains, and less frequently 

 four. 



The glumes are broad, varying much in shape, color, 

 smoothness or hairiness, width and distinctness of keel, 

 length and sharpness of tip. It has been shown that, in 

 general, the second kernel of a spikelet is the heaviest, the 

 first next heaviest, then the third, fourth, etc. 



Flower (Fig. 30). — There are three stamens with thread- 

 like filaments and rather large anthers. The single ovary 

 has two feathery stigmas. There are two lodicules. As was 

 pointed out on page 84, the palet represents the outer 

 perianth whorl, and the lodicules the inner perianth whorl. 



4-10 



AM. 



Fic. 32. — Opening of wheat flower. (Afler Hays.) 



Opening of Flower and Pollination. — Hays has shown (in a 

 variety of spring wheat) that the flowers open early in the 

 morning, the entire process of pollination taking place within 

 about an hour (Fig. 32). Fruwirth notes that, in warm 

 weather, blooming begins at 4:30 a.m., and continues at a 

 rapid rate until 5:30 a.m. From this latter hour until 9:00 



