264 



PASTORAL AND AGRICULTURAL BOTANY 



Sweet Clover. Slender wheat-grass,' tall pigweed, lamb's quarters, 

 sunflower, Russian thistle, and green foxtail. 



Timothy. Rugel's plantain, peppergrass, and sheep sorrel. 



FIG. 115. Red clover of good quality. Natural size and magnified 9 times. 

 (After Brown, Edgar and Crosby, Mamie L.: Imported Low-grade Clover and Alfalfa Seed. 

 Bull, in, Part III, Bureau of Plant Industry, 1907). 



The third point as to the Vitality of the seeds, which the farmer pro- 

 poses to purchase, can only be determined by an actual test of the power 

 of germination of the seeds to be tested (Fig. 117). Some seeds, owing to 

 the fact that the resting period has not been covered, refuse to germinate 



FIG. 116. Imported red clover of low grade. Natural size and magnified 9 times. 

 (After Brown, Edgar and Crosby, Mamie L.: Imported Low-grade Clover and Alfalfa 

 Seed. Bull, in, Part III, Bureau of Plant Industry, 1907.) 



when first planted, while other seeds, such as the clovers, will germinate 

 twelve hours after the "harvest ripeness" stage occurs. In other cases 

 sound and viable seeds are delayed in sprouting by an impermeable seed 

 coat. In practical seed-testing, where one hundred, or more, seeds are 

 placed in the germination chamber, or in a more simple way between the 



