86 AGRICULTURE. 



in the seeds of forage plants, and in case of any doubt 

 samples of such seed should be sent to the nearest experi- 

 ment station or to the Department of Agriculture for ex- 

 amination. 



Purity tests are usually made by weighing out a few 

 ounces of seed which has been well stirred up so as to 

 make the sample uniform. This seed is placed upon a 

 pane of glass under which is a piece of light-colored paper, 

 and the sample is carefully gone over seed by seed with a 

 small forceps until all the impurities are separated out. 

 After again weighing, the percentage of impurity is easily 

 obtained. If the impurity consists of chaft or dirt, the loss 

 will consist only in paying for something which will not 

 grow. This will render necessary the sowing of more than 

 the usual amount of seed to the acre. If weed seeds are 

 present, there will be greater or less loss according to the 

 character of the weeds. Such seeds as Canada thistle, 

 dodder, Russian thistle, chess, wild mustard, cockle, plan- 

 tain, black medic, daisy, penny-cress, wild carrot, wild 

 oats, and a few others, are serious pests. Every farmer 

 should be able to recognize these weed seeds, and avoid all 

 seed which contains any of them even in small amounts. 

 He should also be familiar with the ordinary grass seeds of 

 trade, such as June grass, orchard grass, the common fes- 

 cues, red top, tall meadow oat grass, etc. Grass-seed 

 mixtures almost invariably contain a large proportion of 

 seed of inferior, if not worthless, species, dirt, and chaff, 

 and should be avoided. It is much better to find out what 

 grasses are adapted to one's fields or pastures and to buy 

 such seed separately, mixing it at home. 



If scales are not at hand, the amount of pure seed in a 

 given sample can be approximately learned by placing the 

 pure seed in a small bottle with the impurities in another 

 bottle of similar shape and size. The names of the foreign 

 seeds may be learned from some botanist or experiment 

 station.* 



* The following standards o/ />urity s.re adopted by the U. S. Depart- 

 ment of Agriculture : 

 Asparagus, beans, buckwheat, cabbage, cauliflower, celery, 



