12 



THE SOUECE OF THE DRUG DIOSCOREA. 



Lower leaves all alternate, or the three lowest subapproximate or verticillate. 

 Internodes strictly glabrous. Fruiting racemes many fruited. 



Leaves pubescent beneath 3. D. paniculata. 



Leaves altogether glabrous 3. D. paniviilaia gUibrifoIia. 



Internodes hairy. Fruiting racemes 1 to 4 fruited 4. D. hirticauUs. 



Staminate inflorescences solitary or fasciculate in the leaf axils, and termi- 

 nating the stem 5. D. floHdana. 



1. Dioscor(xi quaternata (Walt.) Gmel. Rhizomes about 1 cm. in 

 diameter, straight or sometimes forked, with few or no short lateral 

 branches. Stems 1 to 2 m. long, rigid and erect below the first node, 

 requiring support above. Lower leaves verticillate by 5's or 6's 



Fig. 1.— Map of the southeastern portion of the United States, showing the distribution of 



Dioscorca quaternata. 



(rarely 4's or T's) ; upper leaves alternate. Petioles of the lower 

 leaves densely pubescent at base and apex, sometimes glabrate in age. 

 Leaf blades cordate, repand, green on both sides, usually strictly 

 glabrous except for the dense pubescence at the insertion of the 

 petiole. Staminate inflorescences paniculate, solitary in the leaf 

 axils, occuring even in the axils of the lower verticillate leaves. 

 Pistillate inflorescences few flowered. Fruit 2 to 3 cm. long, very 

 variable in shape. 



The distribution of this species, as shown in figure 1, is based upon 

 the following material : 



189 



