138 



BOTANY OF CROP PLANTS 



is exposed, for by so doing, a point of attack for molds is 



furnished. 



The palet is about the same length as the lemma, and bears 



two ridges. The styles are short, and the two lodicules are 



conspicuous and vary in the 

 different types. 



Opening of Flower and 

 Pollination. — The blooming 

 of a spike begins slightly 

 above the middle and pro- 

 ceeds from this point upward 

 and downward. The middle 

 flowers of a triplet come to 

 maturity earlier than the 

 laterals. The duration of 

 blooming varies. Three to 

 four days is a good average 

 for a single spike, and seven 

 to nine days for all spikes of 

 a plant. The glumes of a 

 flower remain open from 

 twenty to thirty minutes. 

 This period depends upon 

 weather conditions. 



In two-rowed nodding 

 barley, the lateral flowers 

 bloom with open glumes, 

 while the middle ones seldom 

 open. Four-rowed barley 



almost always blooms with open flowers, both middle and 



side. In two-rowed erect barley, six-rowed barley and 



peacock barley, the flowers bloom with closed glumes. 



It is claimed that, in such cases, the lodicules are too 



- lemma 



itarchv 

 endojpermi 



Fig. 51. — A, barley grain with th 

 "hull;" B, with "hull" removed; C 

 grain in cross-section. 



