496 
WALTER L. C. MUENSCHER 
Table I briefly shows the extent of the work performed. The 
first column of the table gives a list of the species used. The number 
before the name indicates the number of the series for that species. 
With several exceptions two series were performed for each species. 
The second column indicates for how many consecutive days the tran- 
spiration was determined for each series and also the date when the 
work was carried on. The third column gives the number of indi- 
viduals in each jar and the last column contains the total number of 
plants used in this investigation. 
Table II 
Showing Average Amount of Transpiration from the Various Species Used in Series I 
Total Time in 
Days 
Total Water 
Loss in Gm. 
Total Leaf Area 
in Sq, Cm. 
Average Trans- 
piration in Mg. 
per Hour per 
Sq. Dc. Leaf 
Surface 
Species 
Helianthus annuus 
II 
8,027 
20,000 
151 
Impatiens sultani 
30 
10,862 
6,200 
243 
Pelargonium zonale 
20 
8,930 
38,000 
50 
Phaseolus vulgaris 
25 
12,440 
13,400 
155 
Ricinus communis 
60 
25.897 
8,600 
209 
Zea mays 
30 
23.047 
41,000 
78 
Table III 
Showing Average Amount of Transpiration from the Various Species Used in Series II 
Total Time in 
Days 
Total Water 
Loss in Gm. 
Total Leaf Area 
in Sq. Cm. 
Average Trans- 
piration in Mg. 
per Hour per 
Sq. Dc. Leaf 
Surface 
Species 
Helianthus annuus 
5 
1,440 
7,200 
166 
Impatiens sultani 
25 
5.805 
3,800 
255 
40 
11,610 
18,600 
65 
Phaseolus vulgaris 
40 
15,200 
10,100 
156 
Primula sinensis 
40 
6,580 
9,200 
75 
20 
1,900 
5,100 
79 
30 
4,700 
8,024 
82 
Upon examining Tables II and III it will be found that the abso- 
lute amount of water lost for the various species varies very much 
because of the variation in the total amount of leaf surface in the 
several species. It will also be noted that the average quantity of 
water lost per square decimeter of leaf surface, average of upper and 
lower surface, varies from a minimum of 50 mg. in Pelargonium to a 
