VIBURNUM 649 



VIBURNUM PRUNIFOLIUM. Black Haw Bark. The dried bark 

 of the root of Viburnum prunifolium or of V. Lentago (Fam. Capri- 

 foliacese), shrubs or small trees indigenous to the eastern and central 

 United States. The root bark is more highly esteemed than that of 

 the stem and branches. 



f Stem Bark. In transversely curved pieces, or irregular oblong 

 chips, 1.5 to 6 cm. in length, 0.5 to 1.5 cm. in diameter, bark, 0.5 to 

 1.5 mm. in thickness; outer surface brownish-red or grayish-brown, 

 longitudinally wrinkled, periderm occasionally exfoliated, with occa- 

 sional grayish patches of foliaceous lichens and numerous lenticels; 

 inner surface yellowish- or reddish-brown, longitudinally striate; 

 fracture short, periderm brownish-red, inner bark with numerous light 

 yellow groups of stone cells; odor slight; taste astringent and bitter. 



Root Bark. Somewhat resembling the stem bark, but smoother 

 externally, without lichens and having fewer lenticels. 



INNER STRUCTURE. See Fig. 287. 



Powder. Dark brown; calcium oxalate in rosette aggregates or 

 occasionally in rhombohedra, from 0.015 to 0.035 mm. in diameter; 

 crystal fibers usually having rosette aggregates and occasional mono- 

 clinic prisms of calcium oxalate; stone cells large, irregular, thick- 

 walled and strongly lignified, bast fibers comparatively few, lignified. 



Constituents. A bitter, somewhat resinous principle, viburnin; 

 valerianic (viburnic) acid and other organic acids; resin; tannin; 

 calcium oxalate; ash about 10 per cent. 



ADULTERANTS. The barks of one or more allied species, espe- 

 cially Viburnum dentatum, are said sometimes to be substituted for 

 the official bark. 



VIBURNUM OPULUS. Cramp Bark. The dried bark of the stem 

 and branches of Viburnum Opulus (Fam. Caprifoliacese), a shrub 

 with nearly erect branches indigenous to the northern United States 

 and southern Canada, and also found growing in Europe and Asia. 



Description. In transversely curved pieces, occasionally in single 

 quills, from 1 to 10 cm. in length and 5 to 10 mm. in width; bark 0.5 

 to 1.5 mm. in thickness; outer surface light grayish- to blackish- 

 brown; irregularly wrinkled, somewhat scaly, frequently with fine 

 longitudinal and transverse fissures, and numerous prominent brown- 

 ish lenticels; inner surface light yellowish or reddish-brown, fine.y 

 longitudinally striate, fracture short, irregular; inner surface light 

 brown, the middle bark marked by a light-yellow ring enclosing small 

 groups of bast fibers; odor distinct, like valerianic acid; pleasantly 

 bitter. 



INNER STRUCTURE. See Fig. 288. 



