BRIEPER ARTic ee. 
THE NUMBER AND SIZE OF THE STOMATA 
For some educational purposes it is needful to know which plants 
possess the largest, the most numerous, the most readily observable, or the 
most definitely distributed stomata, and what quantities are involved in 
each of these features. The most important work upon the subject thus 
far is by Wetss,t but he includes only a few of those plants used for labora- 
tory study in this country, namely, the common greenhouse plants and those 
readily raised in greenhouses from seed. Accordingly, in continuation of 
similar studies upon other topics as already described in this journal,? I 
have undertaken to obtain exact data upon this subject, with results recorded 
below. The study was begun, and carried well along, by Miss Atice T. 
MiTcHELL, while a senior student in Smith College, but she was unable to 
bring it into final form. I undertook at first simply to complete her work, 
but later I found it better, in order that all the results might represent a 
single method of treatment, to work over the entire subject from the begin- 
ning. The work has been done in the laboratory of plant physiology in 
Smith College, and has had the criticism and advice of Professor W. F. 
GANONG. 
My method of study, in general, was that developed by Lioyp in his 
Tecent investigations3 on the stomata of desert plants. I removed pieces 
of the epidermis from different parts of full-grown representative leaves, 
and dropped the pieces immediately into absolute alcohol. In order to 
test the possible effect of any shrinkage of the epidermis upon the numerical 
results, I made many comparisons of the data yielded by the epidermis alone 
with those vielded by untreated leaves; but I found no appreciable differ- 
ences. I used throughout the same microscope and combination (Zeiss, 
objective DD, ocular 1 with cross hairs as an aid to counting). In counting 
the stomata, I adopted Wetss’s method of counting all those falling within 
the field of vision, the area of which is easily calculated and reduced to 
Square millimeters. For every species I counted the stomata, and calcu- 
lated the mean, from thirty different fields selected at random from epider- 
mis taken from three different plants (or, in two cases only, from different 
* Jahrb. Wiss. Bot. 4:123, 196. 1865-1866. 
* Bor. Gazetre 40: 302. 1905; 45:50. 1908; 452254. 1908; 46:50. 1908, 
3 Ltoyp, F. E., The physiology of stomata. Publ. Carnegie Institution. 1908. 
221] [Botanical Gazette, vol. 46 
