2O THE FORAGE AND FIBER CROPS IN 'AMERICA 



obtained. Or it may be clone as in the seed-testing division 

 of the United States Department of Agriculture, by means of 

 the apparatus shown in this paragraph. 



17. Seed Identification. As grass seeds occur in commerce, 

 the seeds are usually surrounded by the flowering glume and 

 palea, although a portion of the sample may contain naked seeds. 

 The naked seed is the ripened ovulary or fruit known as a 

 caryopsis, as in the case of cereal seeds. (C. A. 60) The 

 flowering glume furnishes means of identification by variations 

 in length, color, and thickness, character or absence of keel, 

 number of nerves, character of position and shape of awn; 

 by the shape, position, and hairiness of the rachilla, or by its 

 absence. When the spikelet is two or more seeded the 

 rachilla exists ; but when, as in timothy and redtop, the spikelet 

 is one-seeded, no rachilla is attached at the base of the palea 

 in the harvested seed. The point of the flowering glume may 

 be blunt or pointed, and may be straight or curved. 



In the case of the seeds of the legumes the general shape 

 and, to some extent, the color and size of seeds furnish means 

 of identification. The relative length of the ridge or raphe, 

 the prominence of the tip of the caulicle or radicle, and the 

 shape and color of the hilum are often characteristic. The 

 pods when present are one of the most certain means of 

 identification. 



18. Germination of Seeds. The practise of seed control sta- 

 tions is to germinate seeds at a temperature of 64 to 68 F. The 

 practise with regard to grass seeds is to raise the temperature 

 during six of the 24 hours to 86 F., as this temperature has been 

 found to promote germination. Kentucky blue grass has been 

 found to germinate better when the temperature is lowered to 

 40 F. a portion of the 24 hours. The time required to test most 

 grass seed has been established at 21 days, timothy and rye 

 grass 14 days, while for the Poas 28 days are required. Legumes 



