TENOPYR: CONSTANCY OF CELL SHAPE 63 
found in the relative dimensions of the cells, the cells in leaf C 
being somewhat broader than long, while in leaf D this relation of 
length to breadth of the cells is reversed. This variability in cell 
TABLE I 
CAMPANULA ROTUNDIFOLIA 
Comparative length and width of the three types of leaves and the corresponding 
dimensions of the cells of the lower epidermis of each type of leaf. Numerals in paren- 
theses show number of counts. Line of measurement = 1 mm 
Basal leaves —— Linear leaves 
eaves 
Length | Width | Length | Width | Length | Width 
Leer An ooo. ee ae eee FY: FAVS 7123, 5.5 | §6: 3. 
Pek ae Call Bite 626) 55.6.0) woes Ie 0.037) 0.036; 0.04 | 0.029) 0.033) 0.03 
Average number of cells (15)......... 26.99 | 27.74 | 24.81 | 33.45 | 29.78 | 32.97 
Leaf “~- be Shiv s eMeE pe ores Se Seles ti 5. ET: 49- 3.5. 1.32: a; 
pata CRE GER CI eo a oie 0.046; 0.047) 0.038) 0.038) 0.036) 0.035 
Average number of cells (15) ......... 21.54 | 21.38 | 26.02 . 92 | 27.75 | 28. 
Leaf ~~ PEE ae ee ee eas eG iy Bs 18, 55. 39. 4.5 
AVerage Cell Gige 125) on oa 0.045} 0.047} 0.035) 0. sap 0.033} 0.034 
as. number of cells (15).......-- 22.02 | 20.91 | 28.52 _ 55 | 29.98 | 28.92 
Cee EME ae ved s Vel Cates = ¥¥. 49. a 
iets CEN Giz@ £96) 23.4% 5 ces ck 0.037| 0.033) 0.043) 0. ee 0.03 | 0.027 
Average sees or cella (8a ys oo eis 26.95 | 29.56 | 25.95 | 26.56 | 32.28 | 35.77 
ROM Be ee ees 10. 19:5 a7. 6. 50. - 
Averaze cell size (15)... dis. Soe tc 0.042) 0.037) 0.035) 0.036) 0.032) 0.033 
Average number of cells (15)......... 23.55 | 26.97 | 28.3 | 27.32 | 30.6 | 29.86 
EPA oe Ee ale ee ee Gea 19. 19. ai. 3 57- 4.5 
Soba COL OG 086) os se ve ee 0.037} 0.039) 0.037) 0.03 | 0.04 | 0,032 
Aver: number of cells a Berea atar 26.74 | 25.62-| 26.61 | 32.36 | 24.7 | 30.31 
‘hetiag e measurement of leaves....... £4.16 | 15.33. |32.5 a 47.16 | 3:33 
Average rere ase of bake gee 0.04 | 0.039) 0.038) 0.034) 0.034 0.032 
Average number of cells (100)........ ‘| 24.85 25-34 | 26.26 | 29.21 | 28.74 | 30-91_ 
Ratio dimensions of leaf. .-........:.. Of 2% 4.64:1 T4.15 $2 
Ratio dimensions of cell. ..........-. toa: 2 ee Gee 4.07 71 
size and cell shape is found in all three forms of leaves examined. 
However, in most leaves as in the final averages, the numbers 
indicate that the cells are nearly isodiametric or somewhat longer 
than they are broad. The table also gives the average measure- 
ments of the cells in fractional parts of a millimeter. 
A glance at the ratio of the length to the width of the cells of 
the lower epidermis of the three forms of leaves shows that the 
percentage of difference between these two dimensions does not 
approach that found between the leaf dimensions. The basal 
leaves are on the average slightly shorter than broad, and their 
epidermal cells are slightly longer than broad, almost isodiametric. 
