Transpiration and the Resistance of Stems 339 



Relation of Length to Pressure 



The following experiments illustrate the variations in resistances 

 of different portions of the same stem. As in the first table the 

 transpiration rate follows the name of the plant, in the second 

 column is the rate obtained by pressure, next the pressure em- 

 ployed and the dimensions of the stem. Columns 5, 6 and 7 give 

 the rates when ^, | and -| respectively of the stem had been re- 

 moved. 



II. 



1234 5 6 7 



AbutiLn 38.5 42 79 40 X J- 1 3 2 2 7 2 3 



40 42 32.5 26.5 23 



41 42.5 32.5 27 23.5 

 39 42.5 32 27.5 23 

 39-5 43 32.5 27.5 23 

 40.5 43 32 28.1 25.5 



Abutilon 2 1 i^s 66.5 40 X -9 S 2 20 15 



i t 



. " 1 47 1" 37-4 40 X -8 i 26 58 34 



Syringa 60 6l 220 40 X - 8 34 3° J 5 



58 61 34 31 16 



56 63 35 3i-5 l6 



59 64 35 31 J 7 



58 64 • 36 3i-5 18 



58 64 39 32 18 



Syringa 58 61 190 30 X I -° 43 3° 21 



4&o 450 I0 3 30X0.6 2 30 I 20 40 



Viburnum 63 58 1 95 40 X -6 43 39 *6 



61 58 44 40 J 5 



60 59 43 3 8 *5 



59 60 41 39 l6 



62 59 41 3 8 l6 



61 59 40 39 l6 



Viburnum 56 65 186 40 X J- 20 16 9 



48 48 222 40 X -9 3 1 2 ° J 5 



Pelargonium I 5 5^7 186 40 X I -° 



1 9 5 52 



16 6 



1 10 c58 



18 r56 



Pelargonium i*o 356 186 40 X 



1 22 310 ^6 40 X 



120 f 24 J86 20X1.0 47 26 *4 



<< 



c< 



.0 



2 3 * 



l2 7 



1« 





2 34 



I« 



I« 





2 35 



1 26 



I« 





2 37 



I" 



16 





238 



I** 



I* 





2 38 



,28 



I» 



.9 



2" 



42 



23 



.8 



2 26 



,58 



I»8 



(I 



