i 4 8 



WEEDS OF FARM LAND 



species that are really characteristic of any type of soil are 

 few in number and comparatively infrequent in distribution, 

 whereas plants which merely exhibit a preference for a partic- 

 ular soil are represented by several species, and are far more 

 often met with. 



TABLE VIII. WEEDS WITH A DEFINITE PREFERENCE FOR CHALK BUT 

 ALSO OCCURRING ON ALL SOILS. 



Of all the weeds classified in this list field scabious {Scabiosa 

 arvensis), bladder campion (Silene inflata}, wild carrot (Daucus 

 carota), and greater knapweed (Centaurea scabiosa} show the 

 greater preference for chalky soil, though pimpernel (Anagallis 

 arvensis] and hogweed (Heracleum sphondylium) run them 

 very close. 



Field scabious (Scabiosa arvensis) is quite commonly dis- 

 tributed, but it rarely occurs in any quantity, and was never 

 seen to reach a position of dominance. 



Bladder campion {Silene inflata) is perhaps rather less 

 frequently seen than the scabious, but it occurs in greater 

 abundance, and occasionally forms the chief weed in the flora 

 on various types of land. 



Wild carrot (Daucus carota) is probably less usual as an 

 arable than as a pasture weed, but in spite of its infrequent 

 occurrence it is sometimes present in such abundance as to be 

 dominant on light and chalky soils. 



Greater knapweed (Centaurea scabiosa) is another of the 



