RELATION OF TRANSPIRATION TO STOMATA 
495 
dimensions. This method is based upon the rapidity with which 
alcohol dehydrates the guard cells when bits of epidermis are dropped 
in absolute alcohol immediately after they are removed from the leaf. 
When once dehydrated these cells become hard and remain permanent 
in size and shape even if they are afterwards mounted in water. 
Since Lloyd (lo) and Eckerson (5) found that the stomata are 
open widest at about 10 o'clock A. M., I removed bits of epidermis at 
this time of the day on bright clear days, placed them in vials of abso- 
lute alcohol and then determined the length and breadth of both guard 
cells and pores for about 25 to 50 stomata for each leaf surface for 
the several species used. From these data I also computed the area 
of one stoma and the amount of stomatal aperture and the number 
of linear units of stomatal pore per unit of leaf area for upper and 
lower surface. 
III. Experimental 
The following tables with short explanations and discussions 
represent briefly the scope and results of this investigation. 
Table I 
Showing the Species and the Number of Individuals of Each Used and When Each 
Were Studied 
Series Species 
Dat 
e 
No. of 
Jars 
No. of 
Plants 
in 
Each 
Jar 
Total 
No. of 
Plants 
I. Helianthus annuus L 
II days- 
-Nov. 
4-15, I914 
10 
2 
20 
5 days- 
-Dec. 
20-24, I9I4 
10 
4 
40 
I. Impatiens sultani Hook 
30 days- 
—Nov. 
4-Dec. 4, 
12 
2-3 
30 
I9I4 
2. Impatiens sultani Hook 
25 days- 
-Dec. 
10, 1914- 
6 
3 
18 
Jan. 
3. 1915 
20 days- 
-Nov. 
4-24, 1914 
10 
I 
10 
2. Pelargonium zonale Willd 
40 days- 
-Dec. 
10, 1914- 
10 
I 
10 
Jan. 
18, 1915 
25 days- 
—Nov. 
4-29, 1914 
ID 
2-4 
32 
40 days- 
-Dec. 
10, 1914- 
10 
4-6 
48 
Jan. 
18, 1915 
I. Primula sinensis Sabine 
40 days- 
—Nov. 
30, 1914- 
10 
I 
10 
Jan. 
8, 1915 
60 days- 
—Nov. 
4, 1914- 
10 
2-3 
21 
Jan. 
4, 1915 
20 days- 
—Jan. 
3-23, 1915 
8 
10 
100 
30 days- 
-Nov. 
4-Dec. 4, 
10 
4 
40 
1914 
2. Zea mays L 
30 days- 
-Dec. 
19, 1914- 
10 
4-5 
45 
Jan. 
18, 1915 
Total 
128 1 
424 
