444 



BIOLOGY AND HUMAN LIFE 



7. Cucumber family. Many varieties of cucumbers, squashes, 

 pumpkins, watermelons, cantaloupes, and gourds are familiar 

 parts of the food supply in all parts of the world. Some of the 

 gourds leave a hard, dry rind when the pulp and seeds are re- 

 moved, and so may be used as vessels or containers. In the 

 luffa the network of bast fibers left when the pulp dries and rots 



out furnishes a useful 

 substitute for a sponge. 

 8. Sunflower family. 

 In some respects this 

 group may be consid- 

 ered the highest family 

 of plants, since it has 

 attained a very high de- 

 gree of specialization of 

 parts through division 

 of labor, and a wide 

 range of adaptation to 

 all sorts of living con- 

 ditions. One tenth of 

 all the seed-bearing 

 plants belong to this 

 family : and while they 

 Fig. 184. The arnica plant (/lr7«cawo7i^awa) never attain to great 



size, they have managed 

 to occupy a large part 

 of the earth's surface. 

 They are of little value 

 to us as food, lettuce and artichoke beino^ the most com- 

 monly used. Chicory is often used as a substitute for or an 

 adulterant of coffee. Dandelion roots and leaves are used to 

 a slight extent. They are important factors in the weed crop 

 at every season of the year that permits plants to grow ; the 

 dandelion comes out almost as soon as the frost goes, and the 

 asters remain until frost kills the parts aboveground. ]Many 

 composites are cultivated, the chrysanthemums being favorite 



From the buds of the flower heads an extract in 



alcohol is prepared for medicinal purposes. It is 



common in upland meadows in parts of Europe 



and in the western part of this country 



