70 INTRODUCTION. 
the lower situations, as in the case of arctic species which grow on 
coast rocks occasionally. 
The Fourth line is somewhat miscellaneous in its subjects. It 
begins with a “Census” of the species, founded upon the pro- 
vincial and sub-provincial, the comital and vice-comital sections 
before explained on pages 8 to 10. The three nos. set after that 
word show the number of provinces, of sub-provinces, and of 
counties (including vice-counties therewith) ascertained for the 
plant under treatment ; usually excluding all those in which it is 
deemed an alien only, as well as any others in which its existence 
is not sufficiently authenticated. Such a census will thus un- 
avoidably fluctuate in respect of its exact numbers, according to 
fluctuations in knowledge or belief. New localities may raise the 
figures, by adding counties or provinces to those previously ascer- 
tained; while occasionally the figures may be reduced lower, either 
through detection of errors or by increased reasons for distrusting 
records of localities suspected to be erroneous. For comparison it 
has appeared desirable to introduce here a Census for Ireland 
also; which is now made available by the publication of Moore 
and More’s Cybele Hibernica,—a very serviceable addition to the 
geographic botany of the British Isles. These Authors divide 
Ireland into twelve “ Districts,” which may be held to correspond 
with the eighteen provinces of this present volume. The numeral 
figure set after the name of “Ireland” will show the number of 
Trish districts in which the species is recorded by the Authors named. 
Details must of course be sought in the Cybele Hibernica itself. 
The remainder of line fourth is devoted to the ‘ Type of Distri- 
bution,’ in accordance with the expositions before given on pages 
23 to 82. Where combinations are used, they will be understood 
to express something intermediate between two types,—a shading 
off from one to the other. Thus, “ British-english type” will 
intend that the species is widely distributed over Britain; but that 
its lessened frequency or comparatively early termination in Scot- 
land, gives to it also somewhat the character of the English type 
of distribution. 
The Fifth line commences an outline of the area or extcusion of 
