154 



BOTANY OF CROP PLANTS 



small, membranous, and ciliate on the upper margins. There 

 are three stamens, and a single pistil with two feathery 

 stigmas. 



Opening of the Flower, Pollination and Fertilization.— 

 Rye is the only common cereal, besides corn, that is regularly 

 cross-fertilized. These two cereals cannot be self-fertiUzed 

 without a reduction in vigor and productivity. Apparently, 



Pjq 25 — Rye (Secale cereale). A, a single spikelet at a joint on the 

 rachis; B, grain, external view; C, grain in cross-section. A, X 2j4; B and C, 



xs- 



no ill effects result from self-fertilization of barley, wheat and 

 oats. According to some observers, the pollen of rye is im- 

 potent on the stigma of the same flower. Fruwirth notes that 

 the flower is completely closed within twenty-five to thirty 

 minutes after it begins to open, providing the stigmas re- 

 ceive pollen. In case the stigmas are not dusted, the flowers 

 remain open much longer. Blooming begins between 5:00 

 and 6 : 00 a.m. and continues until 9 : 00 or 1 1 : 00 a.m. Then 

 blooming decreases throughout the afternoon, becoming 



