horseweed

horseweed
    n 1: erect perennial strong-scented with serrate pointed leaves
         and a loose panicle of yellowish flowers; the eastern
         United States [syn: {horse balm}, {horseweed}, {stoneroot},
         {stone-root}, {richweed}, {stone root}, {Collinsonia
         canadensis}]
    2: common North American weed with linear leaves and small
       discoid heads of yellowish flowers; widely naturalized
       throughout temperate regions; sometimes placed in genus
       Erigeron [syn: {horseweed}, {Canadian fleabane}, {fleabane},
       {Conyza canadensis}, {Erigeron canadensis}]
    

Horseweed \Horse"weed`\, n. (Bot.)
   A composite plant ({Erigeron Canadensis}), which is a common
   weed.
   [1913 Webster]