72 Botanical Society of Edinburgh. 



land is liable to be swept, for these hajjpen generally after the sap 

 has descended, and when therefore the plant is dormant. 



" I may here mention some experiments which have been carried 

 on by my father for five or six years, in order, if possible, to settle 

 the question. He obtained from Messrs. Lawson, of Edinburgh, all 

 the more generally cultivated trees and shrubs, — North British, 

 North American, and North Asiatic, and the result has been as 

 follows. Among the indigenous trees of Scotland, the ash a])pears 

 to stand as well as any other, as it puts forth its leaves late, and 

 loses them early. Of the scarcely indigenous, or naturalized species, 

 the plane-tree appears to be the hardiest, while the birch and Scotch 

 fir will scarcely live a year. Again, Pinus montana and jEscuIus 

 Hippocasianinn, comparatively tender plants, appear to thrive well ; 

 and Pyrus Aucuparia, which is indigenous with us, thrives tole- 

 rably in cultivation. Almost all the willows do well; — Salix Rus- 

 sellianu, fragiUs, cinerea, viminalis, and vitcllina, 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, both trees 

 and shrubs, appear not to suit. Pinus Cembra, Abies picea, black, 

 white, and Norway, have all been repeatedly tried, but seldom lan- 

 guished a year. Even the hardy, shrubby evergreens, which are 

 met witii indigenous, or in every shrubbery on the mainland, as 

 Ilex aquifoUum, Rhododendron ponticum and Jfavum, Vihirnum Tinus, 

 &.C., die almost immediately. Among the best-thriving evergreen 

 shrubs may be mentioned Arbutus mucronata, Cotoneaster Uva-ursi, 

 Hedera Helix, &c. The latter indeed is native, and in some situations 

 thrives remarkal)ly well, as it also does in Orkney. 



" The climate of Orkney and Shetland are much alike, but sci- 

 entific observations have only been recorded of the former. ' Re- 

 garding it,' Mr. Clouston states, ' the high 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 surprise them when we say that our winter is 

 as warm as that of Glasgow, and several degrees warmer than that 

 of Ajjplegarth in Dumfriesshire, on the very southern border. This 

 is owing to the influence of the surrounding ocean, which elevates 

 the temperature of winter as much as it lowers that of summer. 

 Thus, the temperature of Orkney in May, June and July is 7 de- 

 grees below that of Glasgow during these months ; but for the 

 rvhole year the mean annual temperature in Orkney is nearly the 

 same as that in Applegarth, both being about 46°, or 3^ below that 

 of Glasgow.' " 



Mr. Edmonstone goes on to observe, that " the uniformity of tem- 

 perature in Shetland 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 vegetation, for there is not 

 a semblance of arctic, and scarcely (except in a very few instances) 



