WEED MIGRATION 



721 



Artemisia bienniSj Wormwood. 

 Erechtites hieracipoliAj Fireweed. 

 Arctium lappa^ Burdock. 



CiRSIUM LANCEOLATUM, BuU thistle. 



C. ARVBNSE, Canada thistle. 

 C. CANESCENS, WooUy thistle. 

 CiCHORiUM INTYBUS, Chicory. 

 Leontodon autumnalis, Hawkbit. 

 Taraxacum oepicinale. Dandelion. 

 T. ebythrospermum. Red-seeded dandelion. 

 SoNCHus ASPEBj Spiny-leaved sow thistle. 

 Lactuca scakiola, Prickly lettuce. 



L. SCARIOLA VAB. INTEGRATA. 



Lydgodesmia juncea, Lygodesmia. 

 SoLiDAGO CANADENSIS, Goldcnrod. > 



Fig. 548. 



48 



Narrow Sneezeweed (Helenium tenuifoUum) . General aspect of plant 

 and a single head enlarged. 

 (After Chesnut, U. S. Dept. Agr.) 



