EVEEGKEEN TREES IN WINTER. 341 



different parts of the same plant is an important factor causing 

 a great diversity of results in a given experiment ; as we see in the 

 researches of Kröber^^ who found, for instance, that the difference 

 in the amount of transpiration between any two branches taken 

 from the same plant was sometimes greater than the difference 

 between two branches taken from two different plants of the 

 same species. A difference between different plants was observed 

 by me in Thea japonica : some individuals of this plant which 

 I examined either in pot or in garden showed closure of stomata 

 after the " Kobaltprobe," while others had the apertures com- 

 pletely opened at the same time. 



It is, already, well known that a considerable amount of 

 water is given off even in a temperature near 0°C. I witnessed 

 the same fact in the cut-branches of a few evergreen trees. Thus 

 for example (Table IX experiment 21-27) : — 



The amount of transpiration 

 per D dm. per hour, 

 mgr. 

 Thea japonica 25.71 



Ternstrœmîa japonica 24. 84 



Dapliniphyllum onacropodum 22.87 



21.07 



Fiitosporum Tohira 19.99 



Aucuba japonica 13. GO 



13.69 



Pasania glabra 9.90 



Averaççe amount 18.96 



Comparing these results with those of the preceding ex- 

 periments (expt. 1-20), we see that the effect of low temperature 

 upon transpiration seems to vary according to the nature of the 

 plants. Thus in Aucuba japonica, the intensity of transpiration 



1) Kröber, 1st die Transpirationsgrösse der Pflanze ein Maasstab für ihre Anbau- 

 fähigkeit? Landwirtsch. Versuchst., Bd. XXIV, 1895, p. 503. 



