.>10 WEEDS OF AGRICULTURE. 



seasons, kill a oreat many, though it be not the object of 

 fallowing. 



The fallow weeds are principally such as follow : — 

 1. Couch ; 2. Rest-harrow ; 3. Saw-wort (the common 

 Way-thistle) ; 4. Curled Dock ; 5. Tall oat-like Soft-grass ; 

 6. Colt's-foot ; 7. Corn-bindweed; 8. Corn-mint; 9. Sur- 

 face-twitch; 10. Black-grass. Many others might be 

 added ; but if these be subdued, the others must be killed of 

 course. 



1. COUCH {agropyrum repens). Calyx valves pointed or 

 awned, lanceolate, many-ribbed ; florets about five, 

 sharp-pointed, or awned ; leaves flat ; root creeping. 



Until of late years, that botanical science has afforded us 

 better information, it was generally supposed that all couch 

 or twitch was of one sort, or the roots of one species of grass. 

 But many persons observed that some of these roots, on wet 

 soils, were black, and much smaller, and they had locally 

 obtained the name of black twitch. Queries have also been 

 sent to the Farmer's Journal, " What is black twitch ?" In 

 fact, the black twitch, on soils where it prevails, is much 

 worse than the other, because it is wiry and small, and not 

 so easily discharged from the soil; it is also more brittle, 

 and by harrowing breaks short. It is called 



Agrostis repens. Panicle scattered ; branches bare at the 

 base ; florets few ; calyx, inner valve smooth ; root 

 creeping. 



There are two other grasses which have strong creeping- 

 roots, and are indifferently called couch ; these are the holcus 

 mollis and the poa pratensis : they may locally abound, but, 

 as far as my knowledge goes, they are not so common as the 

 agropyrum repens. 



Holcus mollis. Creeping-rooted Soft-grass. Calyx partly 

 naked ; lower floret perfect, awnless ; upper with a 

 sharply bent prominent awn ; leaves slightly downy ; 

 root creeping. Flowers in June and July. 



Poa pratensis. Smooth-stalked Meadow-grass. Panicle 



