94 ACQUIRED CHARACTERS sec. 



stations in wliicli they had accustomed themselves to the pre- 

 vailing external conditions. That the trees themselves — even 

 in the ""arden of Veitshocldieini — came from different stations 

 is a less probable supposition. 



"We can observe every spring in our gardens that the shrubs 

 Avliich belong to the south begin to l)ud later than our own — 

 thev are so accustomed to a certain sli^lit degree of warmth 

 that it has no effect upon them ; their tissue is indifferent 

 towards this degree of warmth, is not stimulated by it. It 

 may thus be assumed that plants whose ancestors grew in cold 

 stations have become accustomed to cold, whicli means in 

 physiological terms that tlieir tissues have gradually been 

 modified simply by the influence of climate. 



In this manner many of our cultivated plants have ac- 

 climatised themselves in a high degree. There cannot well 

 be any doubt that the different kinds of summer and winter 

 corn are forms which, originating from one and the same 

 species, have not only gradually accustomed themselves to 

 ripen at different times, but have also acquired new mor- 

 phological characters. Very remarkable instances of such 

 acclimatisation are described by F. C. Schlibeler in Scandi- 

 navian plants, especially species of cereals.^ Schlibeler finds 

 that — 



1. When various cereals in Scandinavia (Norway and 

 Sweden) are gradually transplanted from the plains to mount- 

 ain districts, they can be accustomed not only to develop in 

 the same, or even in a shorter time than in their native region, 

 but even at a lower average temperature. When sucli grain 

 after it has Ijeen grown for several years in the mountain 

 regions is again sown in its native soil, it ripens at first earlier 



•■ F. C. Schlibeler, Virularlviii Xorceglcum. — Xorrjes ViLdrirjc. Et BUlrdjj til 

 Nord-Europas Naiur- off Kidturhistorie. Bd. i. Universitets-Programni. With 

 inunerous woodcuts in the text, and four maps. Christiania (Dybwad) 1885. Tlie 

 above extracts according to Foslie (Tromsu), Botanisches Centralhlatt, 1886. Bd. 

 xxviii. p. 205. 



