WEED MIGRATION 



741 



Fia. 558. Yarrow (.Achillea millet olium) . Common in the northern hemis- 

 phere. 

 (Drawing by Charlotte M. King.) 



Cyperus esculentus (northern nut grass) (As.). 



Epilobium angustifolium (fireweed) (As.) . 



Erigeron acris (fleabane). 



Erysimum cheiranthoides (treacle mustard). 



Galium, trifidum (bedstraw) (As.). 



Galium aparine (cleavers) (As.). 



Gnaphalium uliginosum (cudweed) . 



Hierochloe borealis (holy grass). 



Juncus tenuis (wire-grass). 



Lepidium apetalum (peppergrass) . 



Mentha arvensis (mint) (As.). 



Myosurus minimus (mouse-tail). 



Oxalis corniculata (field sorrel). 



