816 VII. AEEAS OF SPECIES. 



Various other more subordinate considerations. The lower the number 

 of the province in which it last appears, the earlier is the name of the 

 plant entered in the latitudinal group ; those which do not occur south- 

 ward of 51 being postponed to those which have the full range of lati- 

 tude southward. The proTincial extremes being the same for two or 

 more plants, the sequence of their names is determined by other condi- 

 tions ; — by the subprovinces or counties, as numbered on the map and 

 on pages 526 to 528 in volume third; — by the existence of other 

 (though distrusted) records for places more northerly; — by the likeli- 

 hood of other localities being found, especially in the instances of segre- 

 gate species, the areas of which have been yet imperfectly ascertained ; 

 — by the greater or less probability of the plants being native in the 

 province under view ; &c. &c. 



The counties or vice-counties are also mentioned in the earlier 

 part of the list, where there are few provinces to be enumerated, and 

 ample space is consequently left in the lines. Where provinces or 

 counties become too numerous the range of longitude is substituted, 

 and shown by means of the five vowels. It is chiefly in the three or 

 four degrees of most southerly latitude, that an indication also of the 

 longitudinal extension becomes desirable. The width of southern 

 England, jointly with the far inland extension of several of the pro- 

 vinces there situate, renders an enumeration of those provinces only a 

 very imperfect key to any longitudinal peculiarities in the areas of the 

 species. But in attempting here to sho>y the longitude somewhat more 

 exactly, it was deemed advisable to avoid a further use of numerical 

 figures ; because a repetition of the same nos. or figures, with changed 

 significations, might have proved confusing and troublesome to persons 

 who use this work ; besides the further inconvenience of signs added 

 to distinguish between figures relating to longitudes east and west of 

 Greenwich, The five vowels a e i o u offer a ready substitute, not 

 difficult to keep in recollection. As the lines of longitude are traced on 

 the map in volume third, they form five longitudinal divisions of two 

 degrees each, bounded westward by the lines 8 6 4 2 0. These 

 divisions are sufficiently numerous anJ exact for the purpose here in 

 view. Each of these five divisions may be represented by one of the 

 vowels ; but the first vowel would be applicable only to the Scilly Isles, 

 and to those islets of North Britain which are situate between 8 — 6 of 

 longitude. The following positions will explain the spaces which are 



