52 THE CLIMATAL DISTRIBUTION OF BRITISH PLANTS. 
making in all six zones, and these he called the Infer-Agrarian, 
the Mid-Agrarian, the Super-Agrarian, the Infer-Arctic, the 
Mid-Arctic, and the Super-Arctic Zones. 
From what has been said above as to the similar effects 
of latitude and height above sea level upon climate, it is 
clear that these climatic zones will not reach to the same 
heights in all parts of the country, but that, leaving out 
of account local causes such as soil, or nearness to the 
sea, aS we go northwards there will be a gradual sloping 
down of the limits of the zones, so that a hill of consider- 
able height in the South of England might yet not reach 
into so high a zone as a much lower hill in the North of 
Scotland. 
The Infer-agravian Zone comprises the lowlands south of 
the Humber and Dee, and in the extreme south reaches an 
altitude of nearly 1,000 feet. Its flora includes about six- 
sevenths of the whole number of British flowering plants, 
and as many as 200 are peculiar to this zone. 
Of these 200, the most common is the Travellers Joy 
(Clematis Vitalba). This is found throughout the South 
of England, particularly on chalky soil; it scarcely reaches 
this district as a native, although it is found in many places 
in apparently wild state. 
I can only find two plants confined to this lowest zone 
which have anything like a good claim to be natives of our 
district, the most interesting of these being the rare 
Fritillavia Meleagris or Snake’s-head; this grows in abund- 
ance in a meadow by the Tame, near Tamworth, and 
has also been recorded from one or two other localities in 
our district. The other plant is an aquatic member of the 
Hemlock family, called CEnanthe fluviatile., frequent in the 
Trent, near Burton. 
The second zone, the Mid-agvarian, lies chiefly between 
the Humber and the Clyde, in this area all the lowest land 
belongs to this zone; in its southern limit—South York- 
