1 66 GROWTH AND WORK OF PLANTS 



and bears the stigma which is narrowly elliptical and somewhat 

 broader than the style. The free part of the filaments are curved 

 also to surround the style, bringing the anthers close around the 

 stigma, upon which the pollen is shed before the flower opens, so 

 that self-pollination usually takes place. 



265. This type of flower, called papilionaceous because of 

 its resemblance to a butterfly (papilio), is characteristic of a large 

 number of plants belonging to the important family known as 

 the pulse family or pea family (Leguminosce, sometimes called 

 Papilionacecz), including the peas, beans, clovers, alfalfa, etc. 

 Besides their importance as food for man and animals, they play 

 a very important part in the enrichment of the soil in nitrogen 

 through the nitrogen-fixing bacteria which grow as parasites in 

 their roots. 



The Sunflower. 

 (Helianthus annuus.) 



266. The sunflower is widely cultivated in gardens for its 

 showy flower head, and for the seed, which is considered a 

 healthful food to be given occasionally to poultry and stock. 

 It grows wild along the rich river valleys in some of the Western 

 States. 



The sunflower is an excellent example for the study of the 

 type of flowers which form a head. The " flower head" is made 

 up of a large number of flowers crowded very closely together in 

 a rounded or flattened group on the broad receptacle.* Each 

 one of these flowers is called & floret. In the sunflower head there 

 are two kinds of flowers. The most showy flowers in the head 

 are the long yellow strap-shaped ones on the border of the head, 

 where they extend outward in the form of rays. These are 



* Such flowers are often called compound flowers. The family to which 

 the sunflower belongs is the Composite, and its members are often spoken 

 of as composites. Besides the sunflower it includes such plants as the golden- 

 rod, aster, daisy, yellow-eyed-susan, dandelion, chicory, lettuce, Joe-pye- 

 weed, chrysanthemums. 



