392 BOTANY AND PHARMACOGNOSY. 



based especially on the characters of the stamens. In a small 

 group represented by the ragweed and known as the Ambrosi- 

 ACE^, the anthers, while close together (connivent) are not 

 united, and the corolla in the marginal or pistillate flowers is 

 reduced to a short tube or ring. In a large group, which includes 

 probably 10,000 species and which is considered to be the Com- 

 POSiT.^ proper, the stamens in the tubular fliowers are syngene- 

 sious and the marginal or ray flowers are distinctly ligulate. This 

 group includes the daisy, sunflower, golden-rod, aster, thistle and 

 most of the plants which yield official drugs. 



It may also be added that the Compositae is considered to be 

 the highest and youngest group of plants. 



Taraxacum officinale (Dandelion) is a perennial, acaulescent 

 herb with milky latex; oblong-spatulate, pinnatifid or runcinate, 

 decurrent leaves, and with a i-headed scape, the stalk of which is 

 hollow. The flowers are ligulate, golden-yellow and numerous ; 

 the involucre consists of two series of bracts, the inner one of 

 which closes over the head while the fruit is maturing, afterward 

 becoming reflexed. The fruit consists of a loose, globular head 

 of akenes, each one of which is oblong-ovate and with a slender 

 beak at the apex which is prolonged into a stalk bearing a radiate 

 tuft of silky hairs, which constitute the pappus. The root is fusi- 

 form and usually bears at the crown a number of branches 2 to 5 

 cm. long, having a small pith and other characters of a rhizome. 

 The root is official (p. 458). 



Lactuca virosa (Poison lettuce) is a biennial prickly herb, 

 with milky latex and oblong-obovate, spinose-toothed, runcinate 

 basal leaves and with alternate, somewhat sessile or auriculate, 

 scattered stem leaves, the apex and margin being spinose. The 

 flowers are pale yellow and occur in heads forming terminal pani- 

 cles. The involucre is cylindrical and consists of several series 

 of bracts. The flowers are all ligulate and the anthers are sagit- 

 tate at the base. The akenes are flattish-oblong, and the pappus, 

 which is raised on a stalk, is soft-capillary, as in Taraxacum. 

 The prepared milk-juice is official as Lactucarium (p. 649). 



Eiipatorium perfoliatum (Boneset or Common thoroughwort) 

 is a perennial, branching, pubescent herb (Fig. 270), with oppo- 

 site, connate-perfoliate, long-lanceolate, crenate-serrate leaves, 



