4 FLORA OF THE LAKE DISTRICT. 



range in altitude above sea-level, and by the figures i, 2, 3, 4 

 the zones of altitude in which the plant grows in the Lake 

 district. For tracing out the vertical range of species, Mr. 

 Watson divided the surface of Britain into two ' regions,' and 

 six 'zones' of temperature. The two regions he called 

 ' Agrarian ' and ' Arctic' The Agrarian includes the whole 

 surface of the island at sea-level, and as far up the hills as 

 arable cultivation is possible. This is up to about 600 yards 

 above sea-level in the north of England, and 400 yards in the 

 Scotch Highlands. All above this belongs to the Arctic 

 region, which is so called because its characteristic plants 

 have their headquarters within the Arctic Circle, or, at any 

 rate, in the north. These two regions he divided each into 

 three zones : Super-agrarian, Mid-agrarian, and Infer-agrarian ; 

 Super-arctic, Mid-arctic, and Infer-arctic. Of these six zones 

 the coldest and the warmest, the Super-arctic and the Infer- 

 agrarian, are not represented in the Lake district, but we have 

 all the other four. I begin to count from below, and my 

 zone 1 corresponds to Watson's Mid-agrarian zone; my 

 zone 2 to his Super-agrarian ; my zone 3 to his Infer-arctic ; 

 and my zone 4 to his Mid-arctic. I give a few notes on the 

 local characteristics of these four zones. 



Zone 1 — Mid-agrarian zone of Watson — extends at the Lakes 

 from coast-level to a height of 900 feet upon the hills. The 

 average annual temperature may be estimated at from 45° to 

 48° Fahr. Its upper limit is marked botanically by the cessa- 

 tion of Ulex and fruticose Rubi in the open spaces, of Pyrus 

 Malus and Viburnum Opulus in the woods, and of Alnus 

 glutinosa and Salix fragilis following up the streams. All the 

 larger lakes, Windermere, Derwentwater, Ullswater, Bassen- 

 thwaite, Crummock, Wastwater, and Haweswater, are low down 

 in this zone, and are more or less surrounded and overtopped 

 by thick woods, sometimes planted, but often of native growth. 



Zone 2 — Super-agrarian zone of Watson — includes that 

 portion of the hill-country which lies at an elevation of 



