310 TEXTBOOK OF BOTANY 



the ground cherry (or " husk tomato "), and the petunia 

 belong to the same family. Among the drugs obtained from 

 members of this family are belladonna, hyoscyamus, and 

 stramonium. 



330. The Gourd Family. The cucumber may be taken 

 as a type of this family. The most important cultivated 

 members were mentioned in Chapter I. 



331. The Composite Family. This is the most highly 

 developed and the largest family of angiosperms. It includes 

 about 13,000 species. Not only is the number of species 

 large, but some of the species, such as the thistles and the 

 dandelions, are represented by immense numbers of indi- 

 vidual plants, and are so persistent and so successful in their 

 methods of reproduction that they can be killed out only 

 with the greatest difficulty. The members of the family are 

 called composites because their separate flowers are so closely 

 grouped together in a head that most persons think of the 

 head as a single flower, especially since, just below it, there 

 are green bracts that look like sepals. The flower of a com- 

 posite has five sepals which take the form of a group of hairs, 

 bristles, or scales ; five petals united into a tube that is often 

 (as in the dandelion) prolonged on one side into a strap- or 

 tongue-shaped structure ; five stamens united by their 

 anthers into a tube; and a pistil apparently composed of 

 two macrospore leaves. Sepals, petals, and stamens are 

 inserted above the ovary. The fruit is small, dry, and seed- 

 like, containing a single seed ; the calyx remains attached to 

 the fruit, sometimes, as in the thistle, forming a means by 

 which the fruit may be blown about. Considering the size 

 of the family, not many of its members have been found 

 useful for human food ; among those that are so used are the 

 chicory, endive, lettuce, dandelion, salsify (or vegetable 

 oyster), the artichoke, and the Jerusalem artichoke. Many 

 are grown as ornamental plants, among them the sunflower, 

 daisy, dahlia, chrysanthemum, China aster, and ageratum. 



