WEEDS 379 



Corn Speedwell (V. agrestis), Hemp Nettle (Galeopsis Tetrahit), Red 

 Deadnettle (Lamium purpureum) and other Labiates, Sun Spurge 

 (Euphorbia helioscopia) , and Petty Spurge (E. Peplis). 



A few are biennials, e. g. : 



Spear Thistle (Carduus lanceolatus), Viper's Bugloss (Echium 

 vulgar e). 



Perennial weeds are uncommon in cornfields ; the follow- 

 ing are examples : 



Rest-harrow (Ononis repens), Bush Vetch (Vicia Cracca), Creeping 

 Cinquefoil (Potentilla reptans), Silverweed (P. Anserina), Willow 

 Herb (Epilobium montanum), Coltsfoot (Tussilago Far far a), Field 

 Thistle (Carduus arvensis), Corn Sow-thistle (Sonchus arvensis), 

 Bindweed (Convolvulus arvensis), Field Mint (Mentha arvensis), 

 Broad-leaved Plantain (Plantago major), Dock (Rumex obtusifolius) , 

 Sheep's Sorrel (Rumex Acetosella), Stinging Nettle (Urtica dioica), 

 Couch-grass or Wicks (Agropyron repens). 



(b) Meadow and Pasture Weeds 



Many plants, not usually regarded as weeds, but of little 

 nutrient value, ma}' occur so abundantly in meadows and 

 pastures as to reduce considerably the value of the herbage, 

 and so may be classed as weeds. While annuals are able 

 to thrive in disturbed and prepared ground, they are ill- 

 adapted for the struggle with turf -forming perennials, and 

 so we find that the majority of meadow and pasture weeds 

 are perennials with effective means of vegetative increase. 

 Annuals are relatively few, and it is an interesting fact 

 that among the latter the most persistent are semi -parasites, 

 living to some extent on the roots of the grasses, e. g. 

 Yellow Rattle (Rhinanthus Crista-galli) , Eyebright (Euphra- 

 sia officinalis), Red Eyebright (Bartsia Odontites). Other 

 common annuals in pastures are the Purging Flax (Linum 

 catharticum) and Nipplewort (Lapsana communis). 



Biennials are few, e. g. Goat's-beard (Tragopogon pra- 

 tense) and the Soft Brome-grass (Bromus mollis). 



