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

 (Rumex acetoaella) ; 3, Curled dock (Rumex criapus); 4, Pennsylvania smartweed (Polygonum 

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

 ranthus retroflexus) ; 7, Peppergrass (Lepidium virginicum) ; 8, Field cress (Lepidium eam- 

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

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

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

 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, 

 Polygnacete; 5, Chenopodiacese; 6, Amaranthacese; 7-8, Cruciferae; 9, Leguminosffi; 10, 

 Anagracese; 11, Umbelliferse; 12-13, Plantaginaceee; 14-18, Composite. 



