736 WEED FLORA OF IOWA 



(Atriplex hortense), cock's comb (Rhinanthus crista-galli major 

 and minor), smartweed (Polygonum persicaria), cypress spurge 

 (Euphorbia cyparissias), meadow saffron ( Colchicum autumnale), 

 silky bent-grass (Agrostis spica-venti), wild oats (Avena fatua), 

 chess (Bromus secatinus), quack grass (Agropyron repens), 

 horse-tail (Equisetum arvense). 



L. Danger in his work on weeds and parasites of Germany, pub- 

 lished in 1887, divides the weeds of Germany into two classes: 

 A. Boot weeds, B. Seed weeds. 



A. Root weeds. — Quack grass (Agropyron repens), reed grass 

 (Phragmites communis), bindweed (Convolvulus arvensis), deadly 

 nightshade (Atropa belladonna) , goatweed (Aegopodium roda- 

 graria), sheep sorrel (Rumex acetosella), sour dock (R. crispus), 

 meadow saffron Colchicum autumnale) , marsh marigold (Caltha 

 palustris), mint (Mentha arvensis), thistle (Cirsium arvense, C. 

 alteraceum, C. acaule, C. heterophyllum, C. palustre, C. lan- 

 ceolatum), (Carduus crispus, C. lanceolatus, C. natans), (Onopor- 

 don acanthium) , sow thistle (Sonchus arvensis, S. palustre, S. asper, 

 S. oleraceus), colt's-foot (Tussilago farfara, T. hybrida, T. peta- 

 sites), yarrow (Achillea millefolium), (Leontodon autumnalis) 

 dandelion (Taraxacum officinale), plantain (Plantago coronopus, 

 P. arenaria, P. major, P. media, P. maritima, P. lanceolata) , horse- 

 tails (Equisetum arvense, E. palustre). 



B. Seed weeds. — Chess (Bromus secalinus), (Alopecurus 

 agrestis), wild oats (Avena fatua), (Agrostis spica-venti) , darnel 

 (Lolium temulentum), black nightshade (Solanum nigrum) , black 

 henbane (Hyoscyamus niger), Jimson weed (Datura stramonium) , 

 fool's parsley (Aethusa cynapium), hemlock (Conium maculatum), 

 cowbane (Cicuta virosa), Venus' comb (Scandix pecten-veneris) , 

 buckwheat (Fagopyrum escidentum) , smartweed (Polygonum 

 persicaria) , dooryard knotweed (Polygonum aviculare) , corn cockle 

 (Agrostemma githago), buttercups (Ranunculus septentrionalis, 

 R. flammula, R. arvensis), nettle (Lamium), charlock (Raphanus 

 raphanistrum) , foxglove (Digitalis purpurea), mustard (Brassica 

 arvensis), mayweed (Anthemis arvensis and A. cotula), groundsel 

 (Senecio vidgaris), horseweed (Erigeron canadensis), field mari- 

 gold (Chrysanthemum segetum), Frenchweed (Galinsoga parvi- 

 flora), spurge (Euphorbia cyparissias) , orach (Atriplex hortense), 

 nettles (TJrtica urens, XI. dioica). 



