128 FIRST PRINCIPLES OF AGRICULTURE. 



includes a large number of weeds, of which shepherd's- 

 purse, charlock, and wild radish are prominent examples. 



The Beet Family includes the food-plants, garden- 

 beets, sugar-beets, and spinach, and the mangel-wurzel, 

 an important fodder plant. The sugar-beet is of great 

 importance in Germany and France as a commercial 

 source of sugar, while the mangel-wurzel is extensively 

 raised as a fodder crop. 



The Melon Family is extensive, though it does not 

 include any strictly farm crops. Cucumbers, melons, 

 pumpkins, and gourds are prominent examples of this 

 order : " cucurbs " is a term also applied to this group 

 of plants. 



The Carrot Family includes carrots, parsnips, parsley, 

 and celery, while lettuce belongs to the dandelion family, 

 and the onion and asparagus to the lily family. 



The Hose Family is an important natural order. It 

 includes herbs, shrubs, and trees, to which belong the 

 most important of our fruits. One type is represented 

 by the plum, peach, cherry, apricot, nectarine, and almond ; 

 another, by the raspberry, blackberry, and dewberry ; and 

 still another, by the apple and pear. The bush-fruits, 

 gooseberry and currant, are both members of another 

 distinct natural order. 



Agricultural Classification. While the grouping of 

 plants by the method described is useful, an agricultural 

 classification, which groups the various crops according to 

 their similarity of growth, management, and treatment, is 

 also convenient to the farmer; and the following method 

 permits of a logical discussion of the principles involved 

 in their growth: 



