1 68 CHEMICAL COMPOSITION OF SOIL [chap. viii. 



number of flowering shrubs that are seen on few other 

 kinds of land — the Traveller's Joy {Clematis vitalbd)^ 

 the Mealy Guelder Rose ( Viburnum lantana), the 

 White Beam Tree {Pyrus aria), the Dogwood {Cornus 

 sanguined) being most characteristic ; while of the trees, 

 the Beech, the Yew, and the Cherry are particularly 

 associated with chalk and limestone soils. Leguminous 

 plants are abundant both in the pastures and the waste 

 places, the Horseshoe Vetch {Hippocrepis comosd) 

 being a very sure indicator of a calcareous soil, while 

 the natural home of Sainfoin and Lucerne {Alfalfa) is 

 on the warm, chalky soils of the south and east of 

 England. The lighter chalky soils are notoriously 

 weedy, Fumitory {Fumaria ojfficinialis), Dove's-foot 

 Cranesbill {Geranium molle)^ and Field Buttercup 

 {Ranunculus arvensis) being among the most abundant. 

 Peaty and waterlogged soils also develop a special 

 vegetation which need hardly be considered in detail, 

 since the farmer merely wants to recognise certain plants 

 and other indications that show the need for drainage 

 either in spots or over the whole field. Patches of rushes 

 always indicate stagnant water near the surface, as also 

 the various sedges known to the farmer as Carnation 

 Grass {Luzula, sp.). The occurrence of tufts of Aira 

 ccespitosa also indicates wetness ; and a stagnant, water- 

 logged condition of the soil is shown by the presence of 

 brown rusty deposits in the ditches, accompanied by an 

 iridescent scum on the surface of the water. On digging 

 into such land a layer of peat is generally found below 

 the surface vegetation, and below that a layer of rusty 

 oxides of iron upon the surface of the true soil. The 

 treatment required in such cases is drainage and liming. 



