WEEDS OF THE FARM AND GARDEN 



horn. 



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- 

 62.5; cockle, 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, pratcnsis), velvet grass 

 i, alfalfa: 2, seeds of vellow trefoil: /rr j j \ 



si pod of same; 4, seed of sweel (HolcilS lanatus), espe- 

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



dove? 5 (C. M PO K.)' Ver; 8 ' ^ ^ OWn Seed ! E "B lish 



rye grass (Lolium pcr- 



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

 tail (Cynosurus cristatus), dock (Rumc.r crispus), sheep 

 sorrel (Rume.v Acctosclla), pepper grass (Lepidium apeta- 

 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- 



corded experiments on Fig 3I !- 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- 



^ i 11 rr-i ference in shape. (Hillman and King.) 

 Candolle. Ihis writer 



found that certain members of the mallow, pulse, and 

 mint families had a prolonged vitality. Later 

 Becquerel also made a study of the prolonged 

 vitality of seeds, and he found of the 550 



