TIOLTZ] 



WEEDS 



239 



bud. The hardiness and ease of dispersal of the plantain is 

 shown by its almost universal occurrence in north temperate lati- 

 tude. 



Cultivated flowers and crops are usually exotics or delicate 

 varieties of once wild and hardy species. They need man's aid 

 in the competition for light and food with the coarser weeds. 



Weeds or their seeds often contaminate field crops, necessi- 

 tating troublesome methods of separation. Wheat, clover, and 

 grass seeds are generally thus mixed. Clover sometimes contains 

 as much as forty or fifty per cent of weed seed. Oats have been 

 found mixed with five per cent of mustard. Hay is often ruined 

 Dy squirrel-tail grass. 



COCKLEBUB BURDOCK 



TRAMI'S THAT "HOOK" A RIDE 



Some weeds are poisonous to man and beast. The notorious 

 loco wed] of the Western plains has killed many horses, sheep 

 and cattle. Jamestown (Jimson) weed grows very commonly in 

 city lots and country yards. It is a member of the nightshade 

 family. Children are sometimes killed by eating the seeds. Poi- 

 son ivy may be classed with weeds in this study. It is an almost 

 universal pest in this country. Children should lie taught to recog- 

 nize and avoid it. though some are immune. Nettle, with its 

 prickly hairs which contain a burning acid, is another weed to be 



