76 WILD MEDICINAL PLANTS OF THE UNITED STATES. 



Wood-sorrel, white. See Oxalis acetosella. 

 Wood- violet. See Viola pedata . 

 Worm -grass. See Spigelia marUandica. 

 Worniseed. See Chenopodium anthelminticum. 

 Wormseed, American. See Chenopodium ambrosioides. 

 Wormwood. See Artemisia absinthium. 

 Wormwood, Eoman. See Ambrosia artemisiaefoli.a. 



Xanthium spinosum L. Ragweed family (Ambrosiaceae). 



Spiny clotbur; spiny burseed; thorny clotweed; thorny burweed. 

 An annual weed, 1 to 3 feet high, naturalized from Europe or Asia; in waste 

 ground, Ontario to Florida, westward to Missouri and Texas. 

 ■ Part used. — Leaves (nonofficial). 

 Xanthorrhiza apiifolia L'Her. Crowfoot family (Ranunculaceae). 



Shrub yellowroot; southern yellowroot. 



Low, shrubby, indigenous perennial, 1 to 2 feet high, growing in woods and 

 along river banks, southwestern New York to Florida, chiefly in the moun- 

 tains. 

 Parts used. — Rhizome and roots (nonofficial). 

 Xanthoxylum. See Fagara clava-herculis and Xanthoxylum americanum. 

 Xanthoxylum americanum Mill. Rue family (Rutaceae). 



Synonym. — Xanthoxylum fraxineum Willd. 

 Xanthoxylum; northern prickly ash; toothache-tree. 



Indigenous shrub or small tree, maximum height about 25 feet; common in 

 woods and thickets and along river banks from Virginia, Missouri, and 

 Nebraska northward to Canada. 

 Parts used. — Bark of this or of Fagara clava-herculis official under the name 

 "Xanthoxylum." Berries (nonofficial). 



Xanthoxylum clava-herculis L. Same as Fagara dava-herculis. 

 Xanthoxylum fraxineum Willd. Same as Xanthoxylum americanum. 



Yam, wild. See Dioscorea villosa. 



Yarrow. See Achillea millefolium. 



Yellowroot. See Coptis trifolia, Hydrastis canadensis, and Jejfersonia diphytta. 



Yellowroot, shrub. See Xanthorrhiza apiifolia. 



Yellowroot, southern. See Xanthorrhiza apiifolia. 



Yellowthorn. See Fagara clava-herculis. 



Yellowwood. See Fagara clava-herculis. 



Yerba buena. See Micromeria chamissonis. 



Yerba reuma. See Frankenia grandifolia. 



Yerba santa. See Eriodictyon calif ornicum. 



Youthwort. See Drosera rotundifolia and Heracleum lanatum. 



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