228 POWDERED VEGETABLE DRUGS 



22. (Fig. 41.) ASCLEPIAS. Asclepias. 

 Fl. ex. 60. 



Pleurisy root, E. Knollige Schwalbenwurzel, G. Racine d'as- 

 clepiade tubereuse, Fr. 



The roots of Asclepias tuberosa L., Asclepiadaceae. 



Very light yellowish brown. 



Nearly odorless; nauseating when moist. 



Somewhat pungent and bitter. 



Numerous typical yellow, porous sclerenchyma cells; parenchyma 

 cells rather thin walled containing compound starch granules and 

 prismatic and aggregate crystals of calcium oxalate; large and smaller 

 reticulate and porous ducts. 



Roots of related species may be substituted. 



