SELECTION OF SEED; FARM CROPS. 129 



1. Cereal crops: Wheat, rye, oats, barley, and com. 



2. Forage crops: Grasses and clovers for forage hay and pasture. 



3. Root crops: Turnips, swedes, carrots, and mangels. 



4. Tuber crops: White potato and sweet potato. 



5. Miscellaneous crops: Market-garden and fruit crops. 



Cereal Crops. — The chief object in the growth of 

 cereals is to obtain the grain or seed. They are all 

 annuals, though their natural period, or time of growth, 

 differs, certain of them requiring a longer time for their 

 growth and maturity than others. In the case of wheat, 

 ryC; oats, and barley, the natural period of vegetation has 

 been changed by careful selection and breeding, so that 

 we have both winter and spring varieties, the former 

 seeded in the fall, and the latter in the spring. The 

 winter varieties of wheat and rye, and the spring varie- 

 ties of oats and barley, are more generally grown. Indian 

 corn, or maize, is seeded in spring only. 



The Root System. — In the cereals, the roots branch 

 just below the surface, and each shoot produces feeding- 

 roots, which distribute themselves in every direction to 

 gather food and directly nourish the plant. The roots of 

 the cereals, though they are regarded as shallow feeders, 

 also penetrate to considerable depths, — thirty-six inches 

 or more, — the depth corresponding to some extent with 

 the period of growth, winter wheat and rye showing the 

 deepest roots, and oats and barley, seeded in spring, the 

 shallowest. 



The character of the soil also exercises an influence 

 in this respect. The deeper the root, the more food is 

 acquired ; and the power to resist drouth and other un- 

 favorable conditions is proportionately increased. A soil 

 too dense and hard prevents the penetration and develop- 



