PROBLEM 2. The Kljuis of Vlaiits of the Earth 



Fig. 125 Camoviile is a com- 

 mon composite. About how 

 f/hviy ray flowers surroimd 

 the yellow disc? (Brooklyn 



UDTANIC garden) 



89 



able cottonseed oil, which is used for 

 making oleomargarine, salad oils, and for 

 many other purposes. What is left of 

 them can be ground up to make food 

 for cattle, can be used in making plastics, 

 or spread on the ground as fertilizer. 



We get threads or fibers in a very dif- 

 ferent way from the flax plant. It has 

 beautiful bright blue or white flowers. 

 Although its leaves look somewhat like 

 those of a grass, it is a dicotyledon. The 

 threads which are later woven into linen 

 come from the stems which must be 

 "retted" or rotted in water. This loosens 

 the threads. Its seeds are also used as a 

 source of oil (linseed oil) and as cattle 

 feed. Linseed oil is a part of many paints. 

 There are plants of various families like 

 hemp and jute whose stems or leaves 

 contain tough fibers which are used for 

 making rope or coarse bags. 



Another family of importance to man 

 is the madder family. Among its useful 



members is the cofl'ee plant. Originally 

 at home in Abyssinia, it has been carried 

 to many parts of the w^orld where the 

 cHmate is warm. Two other members of 

 this family are the cinchona (sin-koh'- 

 na) tree, whose bark yields the drug 

 quinine, and the madder, which has been 

 used to dye cloth from the time of the 

 early Egyptians. 



The composites. You have seen daisies 

 in the pasture and dandelions in the lawn. 

 What you have probably always called a 

 daisy blossom is really a tiny bouquet 

 of many small blossoms. The daisy is a 

 very closely packed cluster of two very 

 different kinds of flowers. The yellow 

 portion in the center consists of a large 

 number of tiny flowers packed together 

 so tightly that you need to look closely 

 before you can distinguish them as sep- 

 arate flowers. Around them are the much 

 larger white flowers, called "ray flowers" 

 from their position around the center 



