436 BIOLOGY AND HUMAN LIFE 



important to us, we must remember that weeds (that is, uncul- 

 tivated plants that spring up without our invitation) may be- 

 come a serious problem wherever plants are cultivated, and that 

 every family of plants may furnish pests. 



1. Grass family. Most of our crop plants belong here. In 

 addition to the grasses consumed by horses, sheep, and cattle 

 directly from the ground or stored away as hay, we get from 

 this family all our cereals : corn, wheat, oats, rye, barley, and 

 rice. Sugar cane, the chief source of the world's sugar supply, 

 also belongs to this family, as does the bamboo, w^hich furnishes 

 material for building and for utensils, paper, matting, furniture, 

 parts of vessels and vehicles, and many other things for millions 

 of people in Asia and the adjacent islands. 



2. Palm family. The coco palm furnishes food, clothing, 

 utensils, and such little clothing as they need to large popula- 

 tions in tropical islands. We use the flesh of the fruit, the fiber 

 of the husk, and the oil of the fruit. The hard shell is some- 

 times worked into dippers and other vessels ; it takes a high 

 polish. The date palm is the staff of life to many people in 

 northern Africa and Asia ]\Iinor. The sago palm furnishes 

 masses of starch used as food the world over, since it can be 

 conveniently prepared for storage and shipping. The rattan is 

 used for making furniture, baskets, canes, and other objects that 

 need a material that is tough, light, and flexible. The hard 

 cellulose in the seeds of "vegetable ivory" is used for making 

 buttons, knife and umbrella handles, and other things. 



3. Pineapple family. This family is not related to the pines 

 or to the apples. The fruit has become widely used because it 

 can be shipped safely and because it can be easily canned. 

 From the bast fibers in the leaves a very fine thread is prepared 

 called piha in the Philippines. Only one member of this family 

 is native to the United States, the so-called Spanish moss of 

 Florida, which is prepared for stuffing furniture. 



4. Lily family. Many plants of this family are cultivated for 

 their beauty. On the more utilitarian side we have the common 

 onion, the garlic, and asparagus. 



