ARABLE WEEDS. ASSOCIATION WITH SOILS 151 



arable cultivation. This, of course, does not apply to the 

 Fen land, which is of a specially rich nature, and which is not 

 acid like many of the other peat lands. 



Weed Flora of Twelve Fields on Everton Carr, Arranged in 

 Numerical Order of Frequency. 



The peat on Everton Carr, Nottinghamshire, provides an 

 interesting instance of the weeds that occur when wet, acid 

 peat land is cultivated. The weed flora is very restricted in 

 the number of species composing it, but a few are markedly 

 characteristic of the situation and occur in most fields, often 

 in considerable quantity : Willow-weed (Polygonum persecaria}, 

 spurry (Spergula arvensis), sheep's sorrel (Rumex acetosella), 

 and bent grass (Agrostis stolonifera .?), are usually present and 

 often dominant, and hemp nettle (Galeopsis tetrahif) is also 

 very common, though it seldom dominates the whole of a 



