'~HAMPSHIRE AND CAITHNESS 169 
day observation, that it varies much in its constituents. 
The principal general change is noticed if one travels 
from the south of England to the north of Scotland. 
Great Britain extends in this direction for 700 miles— 
far enough to allow climate to have a marked effect 
as between its extremities. The flora of Hampshire 
is very different from that of Caithness or the Ork- 
neys. But both represent in the main the vegetation 
of that part of the Continent which lies in the same 
latitude, the Hampshire flora being akin to that 
of Northern France, the Caithness flora to that of 
Southern Scandinavia. The likeness is in each case 
heightened by the fact that the rocks of the respective 
areas correspond, producing similar soils, which tend 
to support similar floras. The soft Secondary and 
Tertiary deposits of Southern England are repeated 
in the Paris basin and surrounding area, while the 
ancient gneisses of Scotland are akin to those of Nor- 
way. To quote a few instances of this north and 
south difference coupled with east and west simi- 
larity: the Small-flowered Crowfoot (Ranunculus 
parviflorus), White Bryony (Bryonia dioica), Water 
Violet (Hottonia palustris), Yellow-wort (Blackstoma 
perfoliata), and Black Bryony (Tamus communis), 
all widely spread throughout England and Wales, die 
out in or about the Lake District, and are absent from 
Scotland; the Scale Fern (Ceterach officinarum) gets 
farther north—about half-way up Scotland—before 
it disappears; other plants again, widespread in the 
south, die out before the Mersey-Humber line, or 
even the Severn-Thames line, is crossed. On the 
Continent, the plants enumerated are mainly southern 
in their range. All occur widely in Central and 
