XVII.] EFFECT OF CLIMATE ON CUTTINGS. 297 



De Candolle* some twenty years ago. Cuttings of 

 Populus alba, Carpinns Betulus, Liriodendron Tulip - 

 ifera and catalpa were taken at Montpelier and at 

 Geneva, and they were planted at the latter place 

 in glasses of water with sand at the bottom. The 

 Genevan specimens leafed out first. In the case of 

 the poplar, there was a difference of about twenty - 

 three days in favor of the individual of the colder 

 locality, in that of the carpinus about eighteen days, 

 and in that of the tulip -tree a similar result was 

 obtained when the comparison was restricted to buds 

 of the same size and development. The catalpa of 

 the northern locality developed twenty days in ad- 

 vance of the other. The tulip -tree and catalpa are 

 introduced into Europe from America, and yet they 

 had already physiologically adapted themselves to the 

 various stations in which they grew. My own obser- 

 vations along this line have been somewhat extended, 

 and they confirm De Candolle 's experiments. Several 

 of my students have studied the matter with refer- 

 ence both to cuttings and seeds from different lati- 

 tudes. The following test was made by L. C. 

 Corbett, now professor in the Agricultural College 

 of South Dakota, in 1892 : 



I. Cuttings of Lombardy poplar were procured 

 from southern Maine, and were grown in the green- 

 house alongside similar cuttings from our own 

 neighborhood (central New York). The Maine cut- 

 tings began to unfold their buds two days earlier 

 than those from New York. The cuttings were pulled 

 up and photographed about two weeks after the buds 



•Comptes Rendues, 80, 1369 (June 7, 1875). See also Essay XIX. 



