LEGUMINOUS FORAGE CROPS 145 



151. Impurities and Adulterations. Red clover is now rarely 

 adulterated. In Europe colored grains of sandstone were not 

 uncommonly used. Large quantities of black medic or yellow 

 trefoil seeds have been imported into this country in recent 

 years and have been mixed with red clover and alfalfa 



Red clover seed and a few of its impurities: a Dodder (Cuscula arvensis); b black medic 

 (Medicago lupulina); c red clover (trifolium pra'.ense); d broad-leaved plantain (Plan- 

 tago rugelii); e rib- grass (Plantago lanceolota,. Much enlarged (after Pieters). 



probably more commonly with the latter. (236) The seeds 

 of sweet clover sometimes, although rarely, occur. (250) The 

 mixture of other but useful seeds such as timothy and alsike 

 clover is not uncommon. This is frequently due to the crops 

 growing together, but they may also be artificially mixed on 

 account of the lower cost of the seed. 



The Delaware Station found the average of the pure seed 

 in samples examined to be 93 per cent., with no sample below 

 90 per cent. 1 Of 28 samples examined by the Ohio Station, 

 only one was below 93 per cent. 2 The standard of purity should 

 not be less than 98 per cent. The seeds occurring most fre- 

 quently and in greatest number in clover seed were found by 

 the Nevada, 3 Ohio, 2 and the Iowa* stations, in 70, 28, and 255 

 samples respectively, to be as follows: 



Rugel's plantain, Plantago rugelii Decne 

 Rib-grass, P. lanceolata L. 

 Large bracted plantain, P. aristata Michx. 

 Lady's thumb, Polygonum persicaria L. 



1 Delaware Sta. P,ul. No. 5 (1899). 



2 Ohio Sta. Bui. No. 142 (1903). 



3 Nevada Sta. Bui. No. 47 (1900). 

 *Iowa Sta. Bui. No. 88 (1907), p. 27. 



