COMPOSITE 



339 



A. Lappa, Linn. Common burdock. Fig. 280. Common weed from 

 Europe, with a deep, hard root and bushy top 2-3 ft. high: leaves broad- 

 ovate, somewhat woolly beneath, entire or angled. 



14. CENTAUREA. STAR-THISTLE. CENTAUBEA. 



Alternate-leaved herbs, the following annuals, with single 

 heads terminating the long branches: heads many -flowered, 

 the florets all tubular but the outer ones usually much larger 

 and sterile: scales of involucre over-lapping: torus bristly: 

 akenes oblong, with bristly or chaffy pappus. Cultivated. 



499. Centaurea Cyanus. At the left is an outer or ray tioret; then follow three* 

 details of a disk floret; then follows the fruit. 



C. Ctyanus, Linn. Corn-flower. Bachelor's button. Figs. 231, 499. Gray 

 herb: leaves linear and mostly entire : heads blue, rose or white. Europe. 



C. moschata, Linn. Sweet sultan. One-2 ft., smooth: leaves pinnatifid: 

 pappus sometimes wanting: heads fragrant, white, rose or yellow, large. 

 Asia. 



15. SOLIDAGO. GOLDENROD. 



Perennial herbs, with narrow, sessile leaves: heads yellow, rarely 

 whitish, few-flowered, usually numerous in the cluster, the ray-florets 1-16 

 and pistillate : scales of involucre close, usually not green and leaf -like : 

 torus not chaffy : akene nearly cylindrical, ribbed, with pappus of many 

 soft bristles. Of goldenrods there are many species. They are characteristic 

 plants of the American autumn. They are too critical for the beginner. 



16. ASTER. ASTER. Fig. 227. 



Perennial herbs, with narrow or broad leaves: heads with several to 

 many white, blue or purple rays in a single series, the ray florets fertile: 

 scales of involucre overlapping, usually more or less green and leafy: torus 

 flat: akenes flattened, bearing soft, bristly pappus. Asters are conspicuous 

 plants in the autumn flora of this country. The kinds are numerous, and it 

 is difficult to draw specific lines. The beginner will find them too critical. 



