166 ANNALS OF SCOTTISH NATURAL HISTORY 



" I. The scantiness as compared with that of Shetland. 



" 2. Distinct traces of an Atlantic and Germanic flora on 

 W. and E. sides, although at widest I mile W. to E. more 

 shown, perhaps, in forms than in distinct species. 



" 3. Low altitude of Salix Jierbacea, say 700 feet on the 

 Ward Hill, and alpine aspect of other species at this eleva- 

 tion, e.g. Luz2ila syhaticaT 



Mr. Clarke's description of the island allows a clear idea 

 to be formed of the various types of vegetation that may be 

 expected to be found on it. The wind-swept surface is un- 

 favourable to all woody plants except a few creeping shrubs 

 of dwarf growth. The heathy moorland of the northern 

 two-thirds can have only a few species on it. The rough 

 pasture, the wet moor and pools, the banks of the small 

 streams and the crevices of the rocky coasts should be 

 richer in species, though limited to a considerable extent by 

 neighbourhood to the sea, with liability to the drifting over 

 them of salt spray. The small extent of cultivated ground, 

 its peaty nature, and its exposure to storms and to spray, 

 must limit the number of " colonists " or weeds introduced 

 with cultivation, though several of these are found. 



A list of all the species of vascular plants known to me 

 to have been found on Fair Isle will be followed by some 

 remarks on the list and on individual species recorded in it. 

 I have no direct information as to the abundance or scarcity 



j 



of each species, or as to its relation to cultivated ground, 

 houses, or other indications of the likelihood of its introduc- 

 tion by man's aid ; but probably one is not likely to go 

 much astray in judging of the likelihood of alien origin by 

 applying the information gained in other districts of northern 

 Scotland. The lists kindly sent me by Mr. Beeby and Mr. 

 Bennett, though both based on Mr. Straker's collections, 

 differ in their records of species, indicating that they have 

 been drawn up from different materials ; and Mr. Clarke's 

 collections include a good many not in either list. A 

 number are in all three lists, and, in the absence of more 

 direct information, the relative frequency of at least the less 

 conspicuous species may be inferred from their occurrence 

 in one, or in two, or in all three lists. This is indicated 

 below by the letters following each species, A denoting its 



