VALERIAN 653 



the rhizome and roots of valerian the volatile oil is developed in the 

 sub-epidermal layer. The walls of the trachese and wood fibers are 

 marked by simple pores, except in the primary xylem when the 

 tracheae possess scalariform perforations. The non-glandular hairs 

 are usually unicellular. The glandular hairs are small, having 

 either a uni- or multicellular stalk, and a multicellular summit. 

 Calcium oxalate is wanting. 



VALERIANA. Valerian. The rhizome and roots of Valeriana 

 officinalis (Fam. Valerianacese), a perennial herb indigenous to 

 Europe and Asia, and cultivated in Holland, Germany, England and 

 the New England States, being more or less naturalized in this coun- 

 try as far south as New York and New Jersey. The rhizome is col- 

 lected in autumn, cut into longitudinal slices and dried by artificial 

 heat. There are several commercial varieties, and it is said that some 

 of the drug is derived from Valeriana sylvatica. 



Description. Rhizome upright, slightly ellipsoidal, more or less 

 truncate at both ends, from 2.5 to 4 cm. in length, and 1 to 2 cm. in 

 diameter, usually cut longitudinally into two, four or more pieces; 

 externally dark brown, the upper portion having circular stem- and 

 leaf-scars, the sides sometimes with short branches or stolons from 

 5 to 8 cm. in length, with numerous roots and few root-scars; frac- 

 ture short, horny; internally light brown; odor pronounced, becoming 

 stronger on keeping the drug; taste somewhat aromatic. 



Roots 3 to 10 cm. in length, 0.5 to 1 mm. in diameter, longitu- 

 dinally w.rinkled, and brittle. 



Inner Structure. An epidermal layer of papillose cells, some 

 being modified to root hairs ; a sub-epidermal layer containing suber- 

 ized secretion cells and in which are usually numerous small globules 

 of a volatile oil and occasionally small prismatic crystals; the cells 

 of the cortical parenchyma are filled with starch, some of the cells 

 near the hypodermis containing a few oily globules; an endodermis 

 of thin-walled cells surrounding a pericambium; a central cylinder 

 having 3 to 5 fibro vascular bundles; trachese with simple and bor- 

 dered pores. Older roots show a large pith of starch-bearing paren- 

 chyma, a secondary thickening in the fibrovascular bundles and a 

 periderm of a few layers of cells. Sections of the rhizome show a thin 

 periderm, a cortical parenchyma having scattered fibrovascular 

 bundles, a layer of altered cells of the endodermis, numerpus more 

 or less twisted, collateral, fibrovascular bundles and a large pith. 



Powder. Light to dark brown; starch grains numerous, from 

 0.003 to 0.020 mm. in diameter, spheroidal, plano-convex, polyhedral, 

 2- to 4-compound and each usually with a central cleft; tracheae 



