SECALE CERE ALE I 55 



more rapid again in the evening. The first flowers to open 

 are slightly above the middle of the spike. It has been ob- 

 served that the flowers of rye can be induced to open by 

 rubbing with the hand, or by other mechanical stimulation. 



Maturing of Grain, and Mature Grain. — The anatomical 

 structure of the ovary at blooming time is similar to that of 

 wheat, as are also the changes which take place in the grain 

 during its ripening. 



The mature grain (Fig. 55) is free from the lemma and 

 palet. It is long, narrow, and usually darker in color than 

 wheat. The cross-section of the mature grain shows layers 

 similar to those in wheat, although different from it in details. 



Rye protein usually forms about 6 to 12 per cent, of the 

 grain. Gluten is present in the protein, hence, the flour may 

 be made into porous bread. It wfll be recalled at this point 

 that of the common small cereals, wheat and rye possess glu- 

 ten, while oats and barley do not. The flour from rye is 

 more starchy than that from wheat. 



Germination of Rye. — Under favorable conditions, germi- 

 nation will take place in thirty-six to forty-eight hours. The 

 optimum germinating temperature is 77°F., maximum 87°F., 

 and minimum 33. 8°F., to 35.6°F. 



By deep seeding, rye may send out roots and tillers at the 

 second, third, or even fourth node. As a result rye can be 

 planted deeper than wheat. The coleoptile is closed; the 

 first leaf is rolled and brownish-red, which color distinguishes 

 the rye seedling from other cereals. 



Classification, and Origin of Rye.— The cultivated sorts of 

 rye all belong to the one species, Secale cereale. This origi- 

 nated from Secale anatolicum, one of the subspecies of S. 

 montanum. This stem form differs from S. cereale in the 

 fragile rachis, the smaller, narrower fruit, and^ perennial 

 rootstock. 



Environmental Relations. — Rye is adapted to colder and 



