458 



BOTANY AND PHARMACOGNOSY. 



Adulterants. — The rhizomes and roots of Cypripedium hir- 

 siitum and C. spectabile of the United States are said to be some- 

 times used as adulterants of Senega. 



TARAXACUM.— DANDELION.— The root of Taraxacum 

 officinale (Fam. Compositae), a perennial herb indigenous to 

 Europe and Asia, but now naturalized in all civilized parts of the 

 world (p. 392). The root should be collected in spring or in 

 autumn either directly before or directly after the vegetative 

 activity of the plant. It is used in either the fresh or dried condi- 

 tion, the principal supply of the dried root coming from Europe. 

 The pith of the rhizome portion is liable to be attacked by insects. 



Fig. 197a. — Transverse sections of senega, the two on the left being of the dry drug, 

 and the one on the right showing the appearance after soaking the material in water: R, 

 outer bark; R^, bark on the side having abnormal development of wood; B, inner bark, 

 which gives rise to the "keel" on the drying of the root ; H, wood; C, O, cambium; m, 

 medullary rays; m^, parenchyma developed in place of wood on one side. — ^After Meyer. 



Description. — Somewhat cylindrical, tapering, more or less 

 flattened, slightly branched or broken into irregular pieces 6 to 

 15 cm. long, 5 to 15 mm. in diameter; externally light brown, 

 wrinkled, with numerous rootlet-scars ; crown simple or branched, 

 slightly annulate from numerous leaf-bases; fracture short, horny 

 when dry, tough when damp ; internally, bark light brown, 2 to 6 

 mm. thick, made up of concentric layers of laticiferous vessels 

 and sieve alternating. with white parenchyma, wood lemon-yellow, 

 I to 4 mm. thick, porous and non-radiate ; odor slight ; taste bitter. 



Inner Structure. — See Fig. loi, D. 



Constituents. — The drug contains about 0.05 per cent, of a 

 bitter principle, taraxacin, which gives reactions with certain of 

 the alkaloidal reagents ; it also contains two resins, one soluble in 



