222 ANNALS OF SCOTTISH NATURAL HISTORY 



of the plants. Though these variations in Scottish plants 

 have been critically studied in comparison with the Con- 

 tinental forms to ascertain their correct names, yet their 

 distribution here is by no means accurately known, and the 

 effects of local environment upon them have hardly been 

 looked into. 



The warm thanks of Scottish botanists are largely due 

 to Messrs. Beeby, Ar. Bennett, Druce, H. and J. Groves, Han- 

 bury, E. and W. Linton, Marshall, Rodgers, Shoolbred 

 and Townsend, who, by personal investigations during visits 

 to various parts of Scotland, or by assistance freely rendered 

 to their Scottish colleagues in cases of doubtful identity, 

 and by the publication of their own discoveries in Scotland, 

 have added much to our knowledge of the flora, especially 

 in the critical groups. 



All the work yet recorded on the distribution of the 

 flowering plants and vascular cryptogams is based on the 

 divisions followed by Watson, that is, under counties or 

 their subdivisions (named by him vice-counties), amounting 

 in all to forty-one in Scotland. Except for the islands, these 

 are not natural divisions, though to a certain extent equalised 

 by the inclusion of two of the smallest counties in larger 

 ones, by subdivision of the large counties, and by occasional 

 inclusion of outlying portions with neighbouring counties. 

 The instability of such boundaries has been shown by their 

 readjustment a few years ago, causing alterations in some of 

 his areas. 



A scheme of distribution by river-basins, such as that 

 proposed by the late Dr. Buchanan White, though not 

 altogether free from difficulties, would be more natural, and 

 should be correlated with the existing records, a work that 

 will require both care and time. The most satisfactory 

 system of all would be to show the distribution of each 

 species on a map of convenient size. Thus one might see 

 at once the abundance or rarity, the extended or limited 

 area of occurrence, the restriction to coast, rivers, forests, or 

 mountains, and the northern or southern, eastern or western 

 type of each. An excellent example of such graphic 

 representation is afforded in a series of maps to illustrate 

 the ' Carices ' of Holland in the "Nederlandsch Kruidkundig 



