DicMe's Flora Ahredonensis. 



523 



asterisk, at Cove, in the south of Ireland : those in italics also grow without 

 protection during the whole year at Aberdeen ; those not so distinguished 

 require shelter, some in the winter, and others during the whole year : — 



* Agave americana. 

 ♦Amaryllis revoluta. 



Amaryllis vittata. 

 *Aloysia citriodora. 



Azalea indica. 

 *Biidd'eia globosa, 



Coronilla glaiica. 

 *Calla ethiopica. 

 *Cineraria aurita. 



* Chrysanlhemum indicum. 

 Cyclamen persicmn. 

 Canna indica. 



*Dracocephalum canariense. 



Eucomis striata. 

 ^Fuchsia coccinea. 

 *Hemerocallis japonica. 



Hemerocallis alba. 



Hydrangea discolor. 



Houstonia coccinea. 

 *Ixia crocata. 



Lobelia fidgens. 



Myrtus commimis. 



Mesembryanthemum deltoideum. 

 *Melianthus major. 

 *J\Iimuliis viscosus. 



Olea fragrans. 

 *Oxalis caprina. 



Punica nana. 



Protea argentea. 

 *Rubus roscefolius. 

 * Salvia cserulea. 



Verbena triphylla. 



" The mean temperature of the whole year at Aberdeen is several degrees 

 lower than at Cove and Penzance ; and the reason why several of the plants 

 enumerated require no shelter seems to be, because, in winter, the temperature 

 never falls so low here as to destroy their life, and the extremes of heat 

 throughout the year are not very distant, but no doubt also some of them 

 have become acclimated. Hence, the mean distribution of heat throughout the 

 year is less important than the mean distribution through each month. Many 

 plants which Hve in the open air here would perish during the severer winters 

 of more southerly countries ; and, many which can stand lower degrees of heat 

 than those to which they are exposed at Aberdeen, require, also, greater heat 

 than they experience here in the summer, to enable them to continue healthy 

 and ripen their fruit. 



" Humboldt informs us, that, in reference to the culture of useful vegeta- 

 bles, we must discuss three things for each climate ; the mean temperature of 

 the entire summer, that of the warmest month, and also that of the coldest. 

 Also, that, by adding the mean temperatures of the months which exceed SI'S", 

 that is, of the months in which trees with deciduous leaves vegetate, we 

 shall have a sufficiently exact measure of the strength of vegetation. From 

 the tables already given, it will be seen that here the months from May to 

 September inclusive exceed the temperature referred to : the number of 

 months in which this happens is the same as in the environs of London ; but 

 with us the temperature never rises so high. 



" In this district, the grains principally grown are oats and barley. The 

 latter, in order to be cultivated to advantage, requires (according to Hum- 

 boldt), during ninety days, a mean temperature of from 47"3° to 48'2°. Mr. 

 Playfair {Trans. Royal Soc. Edinb. 1800) proposed to date the vegetating 

 season from 20th March to 20th October; and he assumes 40° as the lowest 

 temperature at which corn will vegetate, and he considers 56° as the mean 

 temperature of a good vegetating season. The same author gives an interest- 

 ing comparative table of the mean temperature of different years — that of the 

 vegetating season, and of the price of meal per boll in these years. A similar 

 table had been prepared as applicable to this neighbourhood, but our limits 

 will not allow its insertion. We have mentioned that the staple products here 

 are barley and oats : wheat and rye also come to perfection, but are not 

 general." .... 



" On reviewing our observations on the plants of this district, we can only 

 specify two instances in which certain species are confined to the neighbour- 

 hood of pprticular rocks, and this we are inclined to consider as accidental. 



