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BULLETIN" 692^ V. S. DEPARTMENT OF AGRICULTURE. 



of redtop, Rhode Island bent, and colonial bent. By the same 

 means, the seeds of velvet bent can be recognized when occurring 

 in South German mixed bent seed. 



IMPURITIES OF COMMERCIAL SEED. 



An examination of many commercial samples of the seeds of redtop 

 and of South German mixed bent shows that their origin, whether 

 domestic or foreign, can usually be determined. The studies of the 

 writer in this connection include domestic redtop seed, redtop im- 

 ported from Europe, South German mixed bent seed imported from 

 Germany, Holland, and England, and a limited number of samples 

 of Rhode Island bent seed from Rhode Island and of colonial bent 

 seed from New Zealand. The samples of domestic redtop seed and 

 of South German mixed bent seed examined were sufficient in number 

 to show the prevaiUng kinds of incidental seeds occurring with these 

 commercial seeds. A smaller number of samples of redtop seed 



Itumez acetosella 



CerastloQ Tulgatum 



Veronlck arvensle 



AoUUca miUafoliiA 



Fig. 9. — Seeds occurring frequently in both American-grown redtop seed and South German mixed hent 

 seed (enlarged and natural size): 1, Sorrel {Rumex acetosella); 2, mouse-ear chickweed (Cerastium vul- 

 gatum); 3, corn speedwell ( Veronica arvensis); 4, yarrow (Achillea millefolium). 



known to have been imported from Europe, 27 in all, represented aU 

 that were available. The result of the examination of the samples 

 of Rhode Island bent seed is supported by observations by the writer 

 of the various plants occurring in fields in Rhode Island, where the 

 Rhode Island bent grass grows abundantly. 



Among the incidental seeds found in domestic redtop seed and in 

 South German mixed bent seed certain kinds are common to both. 

 This is to be expected, since these incidental seeds occur commonly 

 with other kinds of commercial seed of both domestic and foreign 

 origin, owing to the cosmopohtan character of their plants. Four of 

 the kinds found most frequently are shown in figure 9. Exclusive 

 of these kinds, others are confined almost wholly to the domestic 

 redtop seed (fig. 10), and still others are confined to the South Ger- 

 man mixed bent seed (fig. 11). 



The plants represented by some of the kinds of seed considered 

 characteristic of European-grown seed are known to occur in this 

 country, but their distribution and the conditions of their growth are 

 not such as to lead to the presence of their seed in domestic seed to 

 the extent that they appear in the imported seed. Furthermore, the 



