BOTANY 



attain a high limit ot successful cultivation. It is, however, very incon- 

 siderable compared to the elevation at which agriculture flourished in 

 former times. In many places over the wild moors the land can be seen 

 to have been furrowed by the plough at a height at which it is quite 

 impossible for corn crops to be obtained at the present day. In 1825 

 Winch mentions that oats then only grew at some 2,000 feet' above sea- 

 level, wheat at about half that altitude, and barley and rye at stations 

 between these two. In Baker's Flora (1868), the greatest height given for 

 the oat in Weardale is 1,340 feet, for barley 1,000 feet, and for wheat 

 750 feet ; but at the present time much of this arable land is laid down 

 for permanent pasture, and the height at which the oat is cultivated is 

 apparently now reduced to about 800 feet. Above the zone of cereal 

 cultivation and reaching to the rough vegetation of the moors are rich old 

 pastures mown annually for hay, in which the useful agricultural grasses 

 and meadow herbage flourish most luxuriantly. The handsome purple 

 heads of the melancholy thistle {Carduus heterophyllus) are often a striking 

 feature among them, and everywhere in these upland pastures there is an 

 abundance of the mountain pansy {Viola lutea) in all varieties, from the 

 beautiful dark purple to pale mauve, almost white, and yellow. In the 

 damper spots with coarser herbage these meadows in the spring are a 

 blaze of yellow with brilliant masses of the marsh marigold (Caltha 

 palustris) and globe flowers [Trollius europceus). The bird's-eye primrose 

 {Primula farinosd)^ an exquisitely scented and delicately tinted flower, 

 is also commonly distributed among the more marshy places. The 

 boundary between the different types of vegetation is determined not so 

 much by altitudes as by such conditions as soil, drainage, aspect, etc. 

 For example, on the flanks of Kilhope Law, rich natural pastures are 

 found at an elevation of 1,700 feet, but in Burnhope this sinks down to 

 about 1,400 feet. The truth of this reflection is also exemplified by the 

 unusually high region in which regularly inhabited houses are found in 

 Durham. One farmhouse in Highfield above the lead-mines stands at 

 2,000 feet above sea-level, and Clough House on Kilhope Law is occu- 

 pied at 1,700 feet. Even approaching this high altitude, around the 

 farmhouses small gardens are common in which potatoes, rhubarb, 

 turnips and cabbages, onions, gooseberries, strawberries, and even a few 

 roses can be grown with success. In favourable situations on the hill- 

 sides at an altitude of 1,600 feet plantations of beech {Fagus sylvatica), 

 spruce {Abies excelsa), larch {Larix europaa), and Scotch fir {Pinus 

 sy/vestris), withstand the weather and form valuable woods ; the syca- 

 more {Acer pseudoplatamis) also attains a fair size. The hazel {Corylus 

 Ave liana) and alder {Alnus glutinosa) scarcely reach this altitude, and 

 oaks {Quercus Robur) of stunted growth are only met with at a slightly 

 lower level. The common elm {XJlmus campestris)^ which flourishes as 

 a large tree on the western side of the Pennine range, is not indigenous 

 north of the Tees, and even when planted in sheltered situations does not 

 attain any considerable size. The wych elm {Ulmus montana), however, 



• It 13 probable that Winch has here somewhat over-estimated the altitude. 



39 



