66 INTRODUCTION. 
some of the more southerly provinces, while they are thought to 
have been introductions from thence into the more northerly 
provinces, it is found impossible to decide with confidence where- 
about the line of distinction should be drawn. Under suck 
circumstances the enclosed nos. must be somewhat arbitrarily 
apportioned ; and perhaps this sort of optional separation may have 
been made unduly frequent at the border line which runs between 
the English and Scottish provinces, or between the Lowland and 
Highland provinces. The angular enclosures [] are used for 
provinces, in regard to which there is so much distrust that it 
seems better to reject them until reported anew on some reliable 
authority. Errors of name, mistakes about the localities, tem- 
porary casuals and planted examples recorded as if natives, and 
generally any circumstances which lead to an expectation that the 
plant will not long continue to be found in the province, if it ever 
really were seen there, may warrant the use of the angular 
enclosures ; which may thus be construed to mean either decided 
” 
or only doubting rejection. Little linear marks “--” indicate 
absence from the province, usually real, occasionally perhaps ouly 
the want of record. In the latter part of the line one of the three 
words before explained on pages 60 to 62 is introduced, with any 
brief remark added, to show whether the plant is deemed Native, 
or Denizen, or Colonist in this country. 
The Second line gives the range of latitude within Britain by 
the even parallels south and north of the extreme known localities; 
that is, all the true localities ascertained for the species under 
consideration, fall between the two mathematical lines of latitude 
cited, although the area of the plant may not perhaps reach close 
up to either line. The extreme south-west of Cornwall is slightly 
below the fiftieth line of latitude ; so that some plants might have 
been given as “‘49—,” by the rule specified, though it appeared 
not worth while to go below “50—” for the few of them so on 
record. Following the indications of latitude, the names of the 
most southern and most northern counties known for the plant 
are also mentioned. For native species the lines and counties are 
to be understood as indicating only the seemingly native localities, 
