132 WEEDS OF FARM LAND 



than its ally and usually' occurs in very small quantities, never 

 being present in any abundance. 



(2) Lady's mantle (A Ichentilla arvensis] is uncommon both 

 on chalky and heavy land, and possibly is the more intoler- 

 ant of the latter. When it does occur on clay or heavy 

 loam it is usually scarce, but on calcareous soil it is dis- 

 tributed more evenly, and is often present in fair amount. 

 Very occasionally it is dominant or sub-dominant on very light 

 soils or sand, but as a general rule it is insignificant and in- 

 conspicuous. 



Red dead-nettle (JLamium purpureutn) always has the air of 

 being an intruder among arable weeds, as it never seems fully 

 at home in such surroundings. Its preference is for medium 

 loam, and it is very rare on chalk ; so rare that it may almost 

 be considered as absent This dead-nettle is never dominant, 

 and never abundant, but is often present in mere traces. 



The mayweeds (Matricaria inodora and Matricaria chamo- 

 milla) resemble one another in distribution, but the former is 

 much the more common. The scentless mayweed (M. inodora) 

 is frequently dominant or sub-dominant on all soils save chalk, 

 and it is probable that it would dominate still more often if it 

 were not for its habit of clinging to the edges and open spaces 

 of the corn fields, and of refusing to flourish among the corn, 

 even in places that are particularly favourable for its growth. 

 This same habit also accounts for the frequency with which 

 the weed seems to be scarce, as if the crop competition is extra 

 strong the mayweed gives up the struggle at the outset and 

 entirely fails to assert itself. 



Wild chamomile {Matricaria chamomilld) is very rarely 

 found on soil of any calcareous type, and probably the plant 

 should be classified amongst those in section (3) which are in- 

 tolerant of chalk. Although this mayweed is so infrequent it 

 is sometimes dominant, usually on sandy soil, and occasionally 

 on clay. 



Annual meadow-grass (Poa annua) is one of the very few 

 grasses that may fairly be regarded as a true arable weed and 

 not as a mere survival from a previous "seeds" crop. It is 

 frequent on all soils except those of calcareous nature and is 

 often present in some quantity, though it is not often domi- 

 nant. Very occasionally, however, it is so plentiful that it 

 carpets the ground and even receives the local name of twitch 

 (this occurred at Gedling in Notts), but such prevalence is un- 

 usual, the weed being easily kept down by careful cultivation, 



