Igtt] OVERTON—TRANSPIRATION AND SAP-FLOW 107 
plants. It was at once found that the kind of poison used to kill 
the plant very greatly influences the amount of water evaporated, 
and that in many cases the amount of water evaporated greatly 
exceeds the amount transpired by a living plant of the same size 
and under the same conditions. Cut stems were placed in chromic 
acid, picric acid, and HgCl, for 24 hours, until it was certain from 
their appearance that the poison had been carried to the leaves 
and that the whole plant was killed; they were then transferred to 
distilled water. All of the plants in table XI had 17 leaves, each 
of the same size, age, and area. The area of each plant in table 
XII was about three times that of each of the plants in table XI, 
21 large leaves being on each. Plants of approximately the same 
leaf areas and of the same stage of development were chosen for 
controls. The amount of water evaporated from each plant was 
determined by weighing. Tables XI and XII give the results 
of my experiments on this point. 
TABLES XI AND XII 
SHOWING Yeon os IN THE DAILY AMOUNTS OF EVAPORATION FROM PLANTS COM- 
ELY KILLED BY CHROMIC ACID, PICRIC ACID, re Fes Cr, 
AS COMPARED WITH A CONTROL PLANT IN W. 
TABLE XI 
: Percentage 
No. of | guia ; Loss per day in grams Average of water 
: : : 
plant uu a eared 
I 2 3 4 5 6 7 8 ee ae day 
I ..| H,0 0.1| 0.9] 0.6] 0.5] 0.5} 0.5] 0.1| 0.4] 0.3! 0.5] 0.44 81 
II ..| Chromic} 0.1} 0.9} 0.8) 0.8) 0.9] 0.6) 0.5) 0.7} 0.9) 0.5] 0.67 36 
Tit ..| HeCh ¥.2| 2.2) 269] 2G) 1S Y.E O.& 6.91 2-5) 5-3) 1.23 28 
VI ..| Picric 0.7] 0.5] 0.4} 0.4] 0.5] 0.6] 0.4] 0.4] 0.2) 0.4) 0.45 II 
TaBLe XII 
Loss per day in grams A 1 
No. of plant Fluid per ay 
I 2 3 4 5 6 7 8 9 ro 
| See H,0 7.4| §.1| 3.0 o6 6.0 * | * (7 * 108-5 +:8 
Tyce: Chromic 2.6| 2.9] 2.7 re wee 8 Og 8 
fis HgCl, 7.0} 7.6| 7.0} 6.6} 6.5] 6.5) * 2 * \10:4a) $02 
th ere Picric 2.41 1,3 2.71 GOL a 2.5) * 4 7 4 eae 3-6 
* Impossible to take readings on these days, but does not affect average. 
