Chap. XXIV. ACCLIMATISATION. 311 



either pliability of organisation or some constitutional difference. The 

 same individual cherry-tree, when forced, has been observed during succes- 

 sive years gradually to change its period of vegetation. 75 Few pelargo- 

 niums can resist the heat of a stove, but Alba multiflora will, as a most 

 skilful gardener asserts, " stand pine-apple top and bottom heat the whole 

 " winter, without looking any more drawn than if it had stood in a com- 

 " mon greenhouse; and Blanche Fleur seems as if it had been made on 

 " purpose for growing in winter, like many bulbs, and to rest all summer." 76 

 There can hardly be a doubt that the Alba multiflora pelargonium must 

 have a widely different constitution from that of most other varieties of this 

 plant ; it would probably withstand even an equatorial climate. 



We have seen that according to Labat the vine and wheat require accli- 

 matisation in order to succeed in the West Indies. Similar facts have 

 been observed at Madras : " two parcels of mignonette-seed, one direct 

 " from Europe, the other saved at Bangalore (of which the mean tempera- 

 " ture is much below that of Madras) were sown at the same time : they both 

 " vegetated equally favourably, but the former all died off a few days after 

 " they appeared above ground ; the latter still survive, and are vigorous 

 " healthy plants." So again, " turnip and carrot seed saved at Hyderabad 

 " are found to answer better at Madras than seed from Europe or from the 

 " Cape of Good Hope." 77 Mr. J. Scott, of the Calcutta Botanic Gardens, 

 informs me that seeds of the sweet-pea (Lathyrus odoratus) imported from 

 England produce plants, with thick, rigid stems and small leaves, which 

 rarely blossom and never yield seed; plants raised from French seed 

 blossom sparingly, but all the flowers are sterile; on the other hand, 

 plants raised from sweet-peas grown near Darjeeling in Upper India, but 

 originally derived from England, can be successfully cultivated on the 

 plains of India; for they flower and seed profusely, and their stems are 

 lax and scandent. In some of the foregoing cases, as Dr. Hooker has 

 remarked to me, the greater success may perhaps be attributed to the 

 seeds having been more fully ripened under a more favourable climate ; 

 but this view can hardly be extended to so many cases, including plants, 

 which, from being cultivated under a climate hotter than their native one, 

 become fitted for a still hotter climate. We may therefore safely conclude 

 that plants can to a certain extent become accustomed to a climate either 

 hotter or colder than their own; although these latter cases have been 

 more frequently observed. 



We will now consider the means by which acclimatisation 

 may be effected, namely, through the spontaneous appearance 

 of varieties having a different constitution, and through the 

 effects of use or habit. In regard to the first process, there 

 is no evidence that a change in the constitution of the off- 



75 'Gardener's Chronicle,' 1841, p. w m a i so sta nd stove heat, see 'Gard. 

 291 • Chronicle,' 1845, p. 226. 



76 Mr. Beaton, in ' Cottage Gardener,' 77 'Gardener's Chronicle,' 1841, p. 

 March 20th, 1860, p. 377. Queen Mab 439 



