WEEDS OF THE FARM AND GARDEN 



horn, 62.5; cockle, 



black medic, bur clover and sweet clover. The im- 

 purities found in samples examined in Iowa are alfalfa 

 dodder, 4.1; knot weed, 4.1; rib grass or buck- 

 12.5; Canada thistle, 8.3; sheep 

 sorrel, 4.1 ; plantain, 4.1 ; 

 bracted plantain, 4.1 ; 

 yellow foxtail, 33.1 ; 

 curled dock, 8.3. 



Impurities in Orchard 

 Grass. The more im- 

 portant impurities found 

 in orchard grass are, 

 fescue grass (Festuca 

 Fig. 30. Some impurities in alfalfa, pratensis), velvet grass 

 i, alfalfa; 2. seeds of vellow trefoil; /LJ-J,.. }!... \ 

 3! pod of same; 4, seed of sweei (HolciiS lanatus), espe- 

 clover; 5, pod of sweet clover; 6, cially in New Zealand- 

 chicory; 7, spotted clover; 8, bur grown see d ; English 

 clover. (C. M. King.) ,, ,. 



rye grass (Lolium pcr- 



enne), blue pearl grass (Molinia caerulea), crested dog's- 

 tail (Cynosurus cristatus), dock (Rumex crispus), sheep 

 sorrel (Rumex Acctosclla), pepper grass (Lepidium apcta- 

 lum and L. virginicum). 



The Vitality of Weed Seeds. Some weed seeds show 

 prolonged vitality; this 

 is especially true of 

 seeds that belong to the 

 pulse and mallow fami- 

 lies. The earliest re- / z 3 <i j- 2 7 g 

 corded experiments on Fig 3I r . 4> ' seeds of Kentucky blue 

 prolonged vitality of grass, the scales cover the seed; 5-8, 

 seeds are those of De Canadian blue grass. Notice the dif- 

 ference in shape. (Hillman and King.) 

 Candolle. I his writer 



found that certain members of the mallow, pulse, and 

 mint families had a prolonged vitality. Later 

 BecquereJ also made a study of the prolonged 

 vitality of seeds, and he found of the 550 



