308 



LAWS OF VARIATION. 



Chap. XXIV, 



analogous case, namely, that in Sweden tobacco raised from home-^rown 

 seed ripens its seed a month sooner and is less liable to miscarry thai 

 plants raised from foreign seed. 



With the Vine, differently from the maize, the line of practical culture 

 has retreated a little southward since the middle ages ; 60 but this seems 

 due to commerce, including that of wine, being now freer or more easy 

 Nevertheless the fact of the vine not having spread northward shows that 

 acclimatisation has made no progress during several centuries. There is 

 however, a marked difference in the constitution of the several varieties ~ 

 some being hardy, whilst others, like the muscat of Alexandria, require a 

 very high temperature to come to perfection. According to Labat, 61 vines 

 taken from France to the West Indies succeed with extreme difficulty, whilst 

 those imported from Madeira, or the Canary Islands, thrive admirably. 



Gallesio gives a curious account of the naturalisation of the Orange in 

 Italy. Daring many centuries the sweet orange was propagated exclu- 

 sively by grafts, and so often suffered from frosts that it required protection; 

 After the severe frost of 1709, and more especially after that of 1763, so 

 many trees were destroyed that seedlings from the sweet orange were 

 raised, and, to the surprise of the inhabitants, their fruit was found to be 

 sweet. The trees thus raised were larger, more productive, and hardier 

 than the former kinds ; and seedlings are now continually raised. Hence 

 Gallesio concludes that much more was effected for the naturalisation of 

 the orange in Italy by the accidental production of new kinds during 

 a period of about sixty years, than had been effected by grafting old 

 varieties during many ages. 62 I may add that Eisso 63 describes somo 

 Portuguese varieties of the orange as extremely sensitive to cold, and as 

 much tenderer than certain other varieties. 



The peach was known to Theophrastus, 322 b.c. 64 According to the 

 authorities quoted by Dr. F. Kolle, 65 it was tender when first introduced 

 into Greece, and even in the island of Ehodes only occasionally bore fruit. 

 If this be correct, the peach, in spreading during the last two thousand 

 years over the middle parts of Europe, must have become much hardire. 

 At the present day different varieties differ much in hardiness: some 

 French varieties will not succeed in England ; and near Paris, the Pavie 



»wn 



wall: 



ct 



it is, therefore, only fit for a very hot southern climate." 



66 



I will briefly give a few other cases. 

 ised bv M. Eov. withstands o.n\c\ sat 



Magnolia grandifi 



i 



■& 



any other variety can resist. With camellias there is much difference 

 in hardiness. One particular variety of Noisette rose withstood the severe 

 frost of 1860 " untouched and hale amidst a universal destruction of other 



6 ° De Candolle, « Geograph. Bot.,' p. 



339. 



61 < Gard. Chronicle,' 1862, p. 235. 



62 Gallesio, 'Teoria della Ripro- 



1813, p. 20, &c. 

 61 Alph. De Candolle, ' Geograph 



Bot.,' p. 882. 



65 ' Ch. Darwin's Lehre von 



der 



duzione Veg.,' 1816, p. 125 ; and Entstehung,' &c, 1862, s. 87. 

 ' Traite du Citrus,' 1811, p. 359. 



63 ' Essai sur l'Hist. des Orangers,' nicle,' 1865. p. 271 



66 Decaisne, quoted in ' Gard. Chro* 



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