58 TENOPYR: CONSTANCY OF CELL SHAPE 
stituent cells? Are the long narrow stem leaves of many plants 
due to the length and narrowness of their cells as compared with 
those found in the more rounded basal leaves, or to a greater num- 
ber of cell divisions in the long axis of the leaf? Are the cells of 
the lobes of incised leaves wider than those of the constricted por- 
tions of the leaves, or are the constrictions the result of a slower 
rate or shorter duration of cell division? 
Gates (1909) seems to think such a direct relation between cell 
shape and leaf shape is probable. “Increase [in cell size],’” he 
says, “has been greater in one dimension than in another, resulting 
in a change in the relative dimensions of the cells. This in all 
probability accounts for the altered shape of some of the organs, 
as leaves and capsules.” He holds that the greater cell size, to- 
gether with the difference in cell shape of O. gigas, is sufficient to 
have produced external differences between the two plants, with- 
out the introduction of any new factors. Except for stating that 
the anthers of O. gigas, which are about twice as long as those of 
O. Lamarckiana, have cells which are not only larger but rela- 
tively longer than those of the parent plant, Gates does not give 
any comparative measurements on corresponding dimensions of 
organs and their cells, to prove the relation of cell shape and body 
shape. 
According to both Familler (1900) and Goebel (1908) there is 
a direct relation between the light intensity and the form of leaf 
produced in Campanula rotundifolia. Plants placed where they 
were well shaded, instead of developing typical linear stem leaves, 
produced only round leaves on the stem, similar to the basal leaves 
which appear earlier in spring. 
In my cultures of Lobelia Erinus, plants grown in the green- 
house during the dull winter months flowered less profusely than 
during the summer. These winter plants had only spatulate 
leaves along the whole length of the floral shoot and none of the 
small linear leaves which are usually found on the upper part of the 
stem. 
Familler’s explanation for such phenomena is that the light, 
food supply, and other optima are higher for the production of the 
flowers and the long leaves than for the production of the round 
leaves. Thus, it is not until the warm weather of early summer, 
