CHAPTER VII. 
TEMPERATURE 
OF the several conditions upon which depends the 
geological distribution of plants that which is most 
easily recognised, and most generally observed, is tem- 
perature. There are hardy arborescents, such as the 
gooseberry, the currant, and the cherry, which uever fruit 
im warm countries; and there are tropical and sub-tropical 
fruit trees such as the bread-fruit, the love apple, the 
banana, and the grape, which may fruit with us in a hot- 
house, but not in the open air. During the meeting of 
the British Association in Aberdeen, in 1859, at which time 
T held the Chair of Botany in King’s College, I was visited 
by a Polish savant, Professor Bialoblotsky, who was desirous 
of particular information in regard to the temperature of 
the district. Having stated generally his enquiry, he 
said:—‘I have observed indications of the prevailing 
temperature. I see the furze flourishes luxuriantly ; and 
I know of course that the cold is by no means severe. I 
have also remarked that the walnut grows well, but does 
not fruit; and I know thus something of the limit of 
heat in summer both as to degree and duration. But 
there are several details in regard to the duration of 
intermediate temperatures, and of the maxima and minima 
of which I wish to be informed, and also details of con- 
ditions under which they occur.’ 
So may one learn elsewhere much in regard to tempera- 
ture from observation of the vegetation. 
_ The following statements by Schleiden, formerly Pro- 
fessor of Botany at Jena, and afterwards at Dorpat, taken 
