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THE ROYAL SOCIETY OF CANADA 



(3) the disposal and use of the screenings accumulating where the grain 

 is cleaned, and (4) certain results arising from the various uses made 

 of the screenings. 



The extent to which grain is sometimes contaminated by weed 

 seeds is shown by the result of an analysis of a sample representing a 

 car of western-grown flax. The weed seeds made up 16 per cent of the 

 total weight of the car. One ounce contained the following weed 

 seeds: Wild mustard (Brassica arvensis (L.) Ktze. and other Brassica 

 species) 1,051, Tumbling mustard (Sisymbrium altissimum (L.) 1,009, 

 Western false flax (Camelina sativa (L.) Crantz) 429, Flat-seeded 

 false flax (Camelina den tataPers.) 170, Lamb's quarters (Chenopodium 

 album L.) 152,Stinkweed (Thlaspi arvense L.) 106, Hare's-ear mustard 

 (Conringia orientalis (L.) Dumort) 73, Wild Buckwheat (Polygonum 

 Convolvulus L.) 14, Cinquefoil (Potentilla monspeliensis L.) 10. 



A sample representing over 25,000 bushels of wheat contained 

 only 92 • 6 per cent by weight of pure wheat, the remainder being made 

 up largely of weed seeds, chiefly wild oats (A vena fatua L.) Wild buck- 

 wheat and lamb's quarters. These do not represent average conditions, 

 but samples as badly contaminated as the above are by no means rare. 



Occurrence of Weed Seeds in Statutory Grades of 



Western Grain 



In December, 1916, representative samples of the various grades 



of oats were obtained from the Grain Inspector at Fort William. The 



following table indicates the weed seed content per pound of each 



grade : 



Weed Seeds Per Pound in Statutory Grades of Western Oats 



