8 BULLETIN 1045, U. S. DEPARTMENT OF AGEICULTUEE. 



Wiley {19) says that three principal varieties are grown in Russia: 

 One with large white seeds, valued for its high oil production; one 

 with smaller black seeds, which are sweeter and regarded as best for 

 eating; and the intermediate form with striped seeds, used both for 

 food and for oil production. 



The common wild sunflower of the United States often has a much- 

 branched stalk (fig. 2) , with numerous heads 3 to 4 inches in diameter. 

 The yield of silage produced by this plant when grown on rich soil 

 under cultivation is usually somewhat less than that obtained from 

 the Mammoth Russian variety under the same conditions. At Red- 



FiG. 2. — Two rows on the left, Mammoth i:u>siau -uiillciw its ; two rows on the right, wild 

 sunflowers, Redfleld, S. Dak. Both varieties weie seeded on April 28, 1920, and photo- 

 graphed in August. 



field, S. Dak., in 1920 the total crop, green weight, of the wild sun- 

 flower was 13.9 tons per acre, while the Mammoth Russian in an 

 adjoining plat yielded 15.2 tons per acre. 



There has been no extensive development of sunflower varieties 

 in the United States. The seed trade has advertised at times six 

 or eight supposedly different varieties, but many of these are only 

 slightly differing strains or selections of the same variety. Probably 

 the most extensive varietal trial made was that of the Department of 

 Agriculture of Ontario, Canada. In 1894 and 1895 seven varieties 

 were under test at Ottawa.^ These varieties, HeVmnthuR glolwsus^ 



6 Ann. Rpt, Dept. of Agr., Ontario, v^. I, p. 261. 1895. 



