Stomata and Hydathodes in Campanula rotundifolia L . 61 
Seedlings. The cotyledonary leaves of the outdoor and indoor 
seedlings examined had about the same number of stomata per sq. 
mm. on their lower surfaces; but on the upper surfaces the average 
was considerably higher for the indoor seedling. The average, how¬ 
ever, for both surfaces of the two seedlings was quite comparable 
with that noted for the lowest leaf of the normal plant. It was 
remarked that the stomata were all large and well developed. 
Outdoor seedling. 
Lower surface Upper surface 
Area of leaf 
no. of 
av. no. per 
no. of 
av. no. per 
Cotyledon 
in sq. mm. 
stomata 
sq. mm. 
stomata 
sq. mm. 
2nd 
6-i 
443 
72*62 
16 
2*62 
1st 
55 
411 
80*9 
18 
3*27 
Indoor seedling. 
2nd 
6-8 
463 
68*38 
28 
4*12 
1st 
6-4 
517 
8o*8 
4 i 
6-5 
Fig. 3. Curves showing number of stomata per square mm. for upper and 
under surface of “whole” shoot according to position of leaf. 
Curves were plotted, using the number of stomata per sq. mm. 
as abscissae and the position of the leaves, 1st, 2nd, etc., from the 
base upwards as the ordinates (see figs. 3-5). 
2—9 
