SUDAN GRASS AND RELATED PLANTS. 55 



may grow sufficient seed for his own plantings and thus be assured of 

 its purity; (2) that if the farmer finds it necessary to buy Sudan grass 

 seed and his land is free from Johnson grass, he should purchase 

 only seed grown outside the Johnson grass region or from responsible 

 growers in the South who are willing to guarantee its purity; (3) and 

 that if the Sudan grass is to be seeded on land already foul with 

 Johnson grass the presence of seed of the latter is a matter of small 

 importance. 



The southern planter can afford to pay a slight advance in price 

 for seed produced north of 38° north latitude or by responsible 

 growers south of that parallel. (See the map, fig. 13.) It must be 

 remembered, however, that some of the Sudan grass seed handled 

 by northern seedsmen is purchased by them in the South, so that 

 to be absolutely safe the seed must be registered as northern grown, 

 and even then it will not be pure unless the grower has sown seed 

 free from Johnson grass seed and other impurities. 



The Texas Agricultural Experiment Station has done more to 

 safeguard the production of Sudan grass seed than any other agency 

 in the United States. Through the Texas Experiment Association, 

 an organization intended to assist in all movements to improve agri- 

 cultural conditions, a campaign was launched in 1914 to require 

 each bag of Sudan grass seed to be labeled with the name and address 

 of the grower, together with information as to the grade of the seed 

 and whether it had been inspected in the field by a representative 

 of the association. Instructions regarding the proposed grades of 

 seed and the methods of tagging the package offered for sale were 

 issued by the secretary of the association on August 3, 1914. Much 

 good was accomplished by this effort in stimulating the production 

 of pure seed and in acquainting farmers with the extreme care required 

 in such work. 



DESCRIPTIONS OF THE SEEDS OF SUDAN GRASS AND JOHNSON GRASS. 



The seeds of Sudan grass and Johnson grass resemble each other 

 so closely that it becomes a matter of extreme difficulty to detect the 

 presence of small numbers of Johnson grass seeds in the seed of Sudan 

 grass. Bulk lots of Sudan grass seed are easily distinguished from 

 Johnson grass seed on account of their uniformly larger size (fig. 23) , 

 but the variations in size, color, and other factors of appearance are 

 so slight that individual seeds may be indistinguishable except under 

 very close examination and with the aid of a magnifying glass. 

 Certain points of difference in the seeds of these two grasses were 

 pointed out, first by Oakley in 1912 (18, p. 504) and later by the 

 senior writer (23) . No critical investigation of this rather important 

 question was attempted, however, until it was necessitated by the 

 action of horticultural inspectors in certain California counties, who 

 refused to allow the importation of Sudan grass seed, claiming that 



