WEED IMPURITIES IN AGRICULTURAL SEEDS 33 



unreliable and the seed varies from year to year so much 

 that very little that is definite can be given on this point. 



Impurities of Red Clover Seed. The kind of impurities 

 found in red clover seed varies somewhat with the local- 

 ity in which the clover is grown. In the United States 

 the more common impurities reported are as follows: 

 Rugel's plantain (Plantago Rugelii), green foxtail (Seta- 

 ria viridis), lady's thumb (Polygonum Persicaria), lamb's 

 quarter (Chenopodium album), ribgrass (Plantago lance- 

 olata), curled dock (Rumex crispus), yellow foxtail (Seta- 

 ria glauca), sorrel (Rumex Acetosella), large spotted 

 spurge (Euphorbia nutans), bracted plantain (Plantago 

 aristata), timothy (Phleum pratense), witch grass (Pani- 

 cum capillare), smooth crab grass (Digitaria humifusa), 

 crab grass (D. sanguinalis), tumble weed (Amarantus 

 albus), alsike clover (Trifolium hybridum), night-flower- 

 ing catchfly (Silene noctiflora), blue vervain (Verbena has- 

 tata), mayweed (Anthemis Cotula), ragweed (Ambrosia 

 artemisiae folia), barnyard grass (Echinochloa crus-galli), 

 white clover (Trifolium repens), wild pepper grass (Le- 

 pidium virginicum), bull thistle (Cirsium lanceolatum), Can- 

 ada thistle (Cirsium arvense), field dodder (Cuscuta arven- 

 sis), wild carrot (Daucus Carota), black mustard (Brassica 

 nigra), chicory (Chicorium Intybus), yellow trefoil (Med- 

 icago lupulina), five-finger (Potentilla monspeliensis), nim- 

 ble will (Muhlenbergia mexicana and glomerata). 



To illustrate the quality of seed in general use, the fol- 

 lowing statement of red clover seed, analyzed in Iowa, 

 may be given: 



One hundred and thirty samples of weighed red clover 

 were examined for impurities and adulteration, the aver- 

 age per cent of impurities was 1.93, the highest per cent 

 was 33.2, only two samples consisted of pure seed. The 

 following impurities were found in 255 samples of red 

 clover seed in percentages, as follows: Timothy, 64.8; 

 Canada thistle, 9.2; foxtail, 54.0; dodder, 4.0; bull thistle, 



