1 68 Staple don. — On the Plant Communities of Farm Land. 
A number of species common on Chalk are also typical Cotswold 
weeds ; some, however, appear to have rather different frequencies over 
Oolite than on other calcareous soils. The distribution of the following 
plants on the Cotswolds maybe contrasted with their distributions recorded 
elsewhere by Brenchley ; the remarks in inverted commas after each species 
are quoted from this author. 
Papaver Rhoeas. ‘ Often dominant true of the Cotswolds. 
Fumaria officinalis. ‘ Occasionally dominant frequently dominant on the 
Cotswolds. 
Lychnis Githago. ‘ Scarce in distribution ’, occasionally plentiful on the 
Cotswolds. 
Silene Cucnbalus. ‘Twice dominant on sand, usually distributed or occa- 
sional ’, often abundant on Cotswolds. 
Legousia hybrida. ‘Never dominant, often scarce’, frequently very abun- 
dant on Cotswolds. 
Neither Linaria vidgaris nor Cichorium Intybus are plentiful on the 
Cotswolds. 
It would thus appear that the weed communities of the Cotswolds, 
especially when the frequencies of the chief contributing species are taken 
into consideration, are decidedly characteristic, and that they differ both 
from the communities found on ordinary loams and from those found over 
Chalk. 
B. Mid- Wales . These soils are acid in reaction and consequently 
decidedly ‘ sour ’ ; they are by no means sands ; they are intermediate 
between loam and clay, and are -thus ‘ sour ’ soils of a heavier nature than 
those investigated by Brenchley. 1 Bfeavy ‘ sour ’ clays have been studied 
by the present writer near Holsworthy, Devon, and peats have come under 
observation in Mid -Wales, while the flora on sands have been examined 
near Greenhithe, Kent. It is possible, therefore, to contrast the communities 
found on the various grades of ‘ sour ’ soil. 
Below (Table III) is given the range of frequencies for the chief species 
found on four grades of ‘sour’ soils : (i) Peat (Mid-Wales); (2) Non- 
calcareous clay (Devon); (3) Non-calcareous stiff loam (Mid -Wales); 
(4) Sand (deduced from Brenchley ’s papers and the present writer’s 
personal observations in Kent). 
1 See Brenchley, (3 c), p. 149. 
