CHAPTER XII. 



SOCIAL FLOWERS. 



Members of the family Composite are easily recognized; the flow- 

 ers are always in a dense head surrounded by an involucre; with few 

 exceptions, there are five united anthers and a two-cleft style; the 

 ovary is always inferior and the fruit an akene. Identification of 

 species in a family often thousand is, of course, difficult; some of the 

 primary divisions of the order are based upon characteristics seen 

 clearly only under the microscope. So the identification of Compos- 

 itse is usually undertaken only by professional botanists, and the 

 laity do well to recognize the principle of division of labor, and ask 

 specialists to name these plants. But since a botanist may not al- 

 ways be accessible, and because this group contains many of our most 

 handsome and interesting plants, native and cultivated, a brief de- 

 scription of some of the most common native Compositae is here 

 given. 



The group Tubuliflorae includes all the Compositae having tubular 

 flowers, whether or not they have ray flowers also. The Aster tribe 

 is one of this group, and includes many common orders, the greater 

 number of them summer and autumn -blooming plants. Some of 

 them are referred to in the Supplement to Chapter III. Not all of this 

 tribe resemble asters in general appearance . The gum plant or resin 

 weed, Grindelia, belongs here; it is not so common in the south, but 

 farther north the species G. cuneifolia, Nutt., abounds in salt 

 marshes and is collected in great quantities for the manufacture of a 

 medicine of the same name, a medicine that, like the cascara, was 

 discovered by the Indians, and is now in general use. The heads 

 have yellow rays, and are rather large and showy; the involucres are 

 covered with a milky resin that is the valuable product of the plant. 

 Heterotheca grandifl.ora y Nutt., is a very common tar-weed of the 

 south; it is a tall, stiff, coarse plant, resinous, ill scented and usually 

 dust laden; the flowers are of medium size, and have numerous yel- 

 low rays; the fruits have a rusty pappus. 



