F. Rolle (24/65. 'Ch. Darwin's Lehre von der Entstehung' etc. 1862 s. 87.), it was tender when first introduced into Greece, and even in the island of Rhodes 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 hardier. At the present day different varieties differ much in hardiness: some French varieties will not succeed in England; and near Paris, the Pavie de Bonneuil does not ripen its fruit till very late in the season, even when grown on a wall; "it is, therefore, only fit for a very hot southern climate." (24/66. Decaisne quoted in 'Gardener's Chronicle' 1865 page 271.)
I will briefly give a few other cases. A variety of Magnolia grandiflora, raised by M. Roy, withstands a temperature several degrees lower than that which any other variety can resist. With camellias there is much difference in hardiness. One particular variety of the Noisette rose withstood the severe frost of 1860 "untouched and hale amidst a universal destruction of other Noisettes." In New York the "Irish yew is quite hardy, but the common yew is liable to be cut down." I may add that there are varieties of the sweet potato (Convolvulus batatas) which are suited for warmer, as well as for colder, climates. (24/67. For the magnolia see Loudon's 'Gardener's Mag.' volume 13 1837 page 21. For camellias and roses see 'Gardener's Chronicle' 1860 page 384. For the yew 'Journal of Hort.' March 3, 1863 p 174. For sweet potatoes see Col. von Siebold in 'Gardener's Chronicle' 1855 page 822.)]
The plants as yet mentioned have been found capable of resisting an unusual degree of cold or heat, when fully grown. The following cases refer to plants whilst young. In a large bed of young Araucarias of the same age, growing close together and equally exposed, it was observed (24/68. The Editor 'Gardener's Chronicle' 1861 page 239.), after the unusually severe winter of 1860-61, that, "in the midst of the dying, numerous individuals remained on which the frost had absolutely made no kind of impression." Dr. Lindley, after alluding to this and other similar cases, remarks, "Among the lessons which the late formidable winter has taught us, is that, even in their power of resisting cold, individuals of the same species of plants are remarkably different." Near Salisbury, there was a sharp frost on the night of May 24, 1836, and all the French beans (Phaseolus vulgaris) in a bed were killed except about one in thirty, which completely escaped. (24/69. Loudon's 'Gardener's Mag.' volume 12 1836 page 378.) On the same day of the month, but in the year 1864, there was a severe frost in Kent, and two rows of scarlet- runners (P. multiflorus) in my garden, containing 390 plants of the same age and equally exposed, were all blackened and killed except about a dozen plants. In an adjoining row of "Fulmer's dwarf bean" (P. vulgaris), one single plant escaped. A still more severe frost occurred four days afterwards, and of the dozen plants which had previously escaped only three survived; these were not taller or more vigorous than the other young plants, but they escaped completely, with not even the tips of their leaves browned. It was impossible to behold these three plants, with their blackened, withered, and dead brethren all around, and not see at a glance that they differed widely in constitutional power of resisting frost.
This work is not the proper place to show that wild plants of the same species, naturally growing at different altitudes or under different latitudes, become to a certain extent acclimatised, as is proved by the different behaviour of their seedlings when raised in another country. In my 'Origin of Species' I have alluded to some cases, and I could add many others. One instance must suffice: Mr. Grigor, of Forres (24/70. 'Gardener's Chronicle' 1865 page 699. Mr. G. Maw gives ('Gardener's Chronicle' 1870 page 895) a number of striking cases; he brought home from southern Spain and northern Africa several plants, which he cultivated in England alongside specimens from northern districts; and he found a great difference not only in their hardiness during the winter, but in the behaviour of some of them during the summer.), states that seedlings of the Scotch fir (Pinus sylvestris), raised from seed from the Continent and from the forests of Scotland, differ much.