309] FLORA OF COLUMBIA AND VICINITY 167 



579. O. cymosa Small \_X. cymosa Small]. 

 Very common in woods, fields and waste places. 

 Ontario to Michigan and Nebraska; Florida to Texas. 



Family 55. LINACEAE Dumort. Flax family. 



225. LINUM L. Flax. 



580. L. usitatissimum L. Common flax. 

 Waste places; rare. 



Native of the Caucasus, thence to all temperate lands. 



Family 56. RUTACEAE Juss. Rue family. 



226. XANTHOXYLUM L. Prickly ash. 



581. X. fraxineum Willd. \_X. Americamtm W\\\?\. 

 Bottom lands and open thickets; frequent. 



Quebec and Ontario to Minnesota and South Dakota; 

 Georgia to the Indian Territory. 



227. PTELEA L. Hop-tree. 



582. P. trifoliata L. 

 Common on rocky banks. 



Connecticut to Minnesota; Florida to Texas. 



Family 57. SIMARUBACEAE DC. Quassia family. 



228. AILANTHUS Desf. Tree of heaven 



583. A. glandulosa Desf. 



A frequent escape along roadsides. 

 Eastern Asia, thence to the United States. 



Family 58. POLYGALACEAE Reichenb. Milkwort family. 



229. POLYGALAL. Milkwort. 



584. P. verticillata L. Whorled milkwort. 

 Sterile hills and red clay barrens; scarce. 



Maine and Quebec to Saskatchewan; Florida to Texas 

 and Utah. 



