Fio. 96. Weed seeds: 1, Night-flowering catchfly (Silene erectifolid) ; 2, Sheep's sorrel 

 (Rumex acetosella) ; 3, Curled dock (Rumex crispus); 4, Pennsylvania smartweed (Polygonum 

 pennsylvanicum); 5, Lamb's quarter (Chenopodium album); 6, Tumbling pigweed (Ama- 

 ranthus retroflexus) ; 7, Peppergrass (Lepidium mrginicuni) ; 8, Field cress (Lepidium cam- 

 pestre); 9, Yellow trefoil (Medicago lupulina); 10, Evening primrose (Onagra biennis); 11, 

 Wild carrot (Daucus carota); 12, Rugel's plantain (Plantago Rugelii); 13, Buckhorn (Plan- 

 tayo lanceolate); 14, Ox-eye daisy (Chrysanthemum leucanthemum) ; 15, Canada thistle (Cnicue 

 arvensis); 16, Bull thistle (Cnicus lanceolatus) ; 17, Yarrow (Achillea millefolium) ; 18, Dan- 

 delion (Taraxacum officinale); A, ventral side; B, dorsal side. 1, Caryophyllacese; 2-4, 

 Polygnacese; 5, Chenopodiacese; 6, Amaranthacese; 7-8, Cruciferse; 9, LeguminosaB; 10, 

 Anagracese; 11, Umbelliferae; 12-13, Plantaginacese; 14-18, Compositse. 



