126 FIRST PRINCIPLES OF AGRICULTURE. 



the quality of the seed is low, since out of one hundred 

 pounds only twenty-two and five-tenths pounds consist of 

 pure germinating seed. Good seed shows a high percen- 

 tage of both purity and germinating power. 



To test germination, two lots of at least one hundred 

 seeds each are selected, and placed under conditions favor- 

 able for germination ; viz., moisture, warmth, and air. A 

 box containing a thin layer of fine soil, kept well moist- 

 ened, and in a warm place, answers the purpose nicely. 

 The chief precautions to observe are to keep the material 

 moist and the temperature between 80 to 90 F. 



Plants are classified by botanists into families or nat- 

 ural orders; by farmers into groups, made distinct by 

 methods of rotation or other local causes. 



Botanical Classification. This is a useful guide 

 to the farmer in indicating habits of growth, as well as 

 methods of manuring and management, since plants of 

 common origin or ancestry, though differing in outward 

 form, are quite likely to be benefited by the same kinds 

 of food, to be subject to the same class of diseases, and 

 to be attacked by the same kind of insects. The differ- 

 ent families also include a number of plants not useful 

 as farm or garden crops, though all possess certain char- 

 acteristics in common. 



The Grass Family. The first natural order in point 

 of usefulness is the grass family. This includes the ce- 

 reals, wheat, rye, oats, barley, corn, and rice, valuable 

 chiefly for their seed or grain ; and the grasses, valuable as 

 hay and pastures, of which timothy, orchard grass, rye 

 grass, blue grass, and red-top, are prominent examples. 



The Family which includes the Potato, valuable 



