431 



any other, as it puts forth its leaves late and loses them early. Of the scarcely indige- 

 nous, or naturalised species, the plane-tree appears to be the hardiest ; while the birch 

 and Scotch fir will scarcely live a year. Again, Pinus montana and ^sculus Hippo- 

 castanum, comparatively tender plants, appear to thrive well ; and Pyrus aucuparia, 

 which is indigenous with us, thrives tolerably in cultivation. Almost all the willows 

 do well ; — Salix Russelliana, fragilis, cinerea, viminalis and vitellina, among the best. 

 The alder is rather too early in putting forth its leaves, but some poplars appear to do 

 well, especially the white Scotch, black Italian and Lombardy, and Populus nigra is 

 indigenous. Oak and beech will not thrive at all. Generally speaking, evergreens, 

 whether trees or shrubs, appear not to suit. Pinus Cembra, Abies Picea, black, white 

 and Norway, have all been repeatedly tried, but seldom languished a year. Even the 

 hardy shrubby evergreens, which are met with indigenous, or in every shrubbery on the 

 mainland, as Ilex Aquifoliutn, Hhododeridron ponticum and flavum, Viburnum Tinus 

 &c., die almost immediately. Among the best thriving evergreen shrubs may be men- 

 tioned Arbutus Uva-ursi, Cotoneaster mucronata, Hedera Helix, &c. The latter in- 

 deed, is native, and in some situations thrives remarkably well, as it also does in Orkney. 



" The climate of Orkney and Shetland are much alike, but scientific observations 

 have only been recorded of the former. 'Regarding it,' Mr. Clouston states, 'the hioh 

 latitude of Orkney will no doubt induce many well-informed persons even in Scotland 

 to suppose that our winter is much colder than that of any other country, and it may 

 sui-prise them when we say that our winter is as warm as that of Glasgow, and several 

 degrees warmer than that of Applegarth in Dumfriesshire, on the very southern border. 

 This is owing to the influence of the surrounding ocean, which elevates the tempera- 

 ture of winter as much as it lowers that of summer. Thus, the temperature of Orkney 

 in May, June and July, is 7 degrees below that of Glasgow dnring these months • but 

 for the whole year, the mean annual temperature in Orkney is nearly the same as that 

 in Applegarth — both being about 46 degrees, or 3f below that of Glasgow.'" 



Mr. Edmonston goes on to observe, that " the uniformity of temperature in Shet- 

 land strikes every one; and a remarkable feature in the climate is the great and almost 

 constant humidity. These causes no doubt have a great influence on the veo-etation 

 for there is not a semblance of arctic, and scarcely (except in a very few instances) of 

 alpine vegetation throughout the whole islands. This is certainly rather what might 

 be expected than otherwise ; but there are other anomalies which cannot be altogether 

 referred to climate ; and the extreme scantiness of the Flora is remarkable, consider- 

 ing the extent of the islands, and the variety of soil, exposure and situation which they 

 present." 



The flowering plants (including the grasses) hitherto observed in Shetland, extend 

 to 94 genera and 178 species ; while those found in the district of Moray amount to 

 333 genera and 692 species ; and even in a range of sixteen miles round Aberdeen 

 there have been found 287 genera and 562 species ; and in a similar extent round Ed- 

 inburgh, the numbers are 389 genera and 908 species — while the flowering plants of 

 Great Britain extend to 523 genera and 1594 species. The proportion of species to 

 genera is also least in Shetland and Aberdeenshire, being only 2 to 1, whereas in the 

 Edinburgh district it is 2^ to 1 ; and in Britain generally it is 3 to 1. 



The statements in Mr. Edmonston's paper led to some interesting conversation 



in the course of which Professor Graham remarked, as a phenomenon which has not 

 hitherto received a satisfactory solution — the entire destruction or absence of wood in 

 many parts of Scotland where once it evidently abounded, and where the change can- 



