The Stature and Chromosomes of Oenothera gigas, De Vries. 533 
as the epidermal, the volume was reckoned as tbe product of its 
tkree dimensions, two of whicli were known from Observation and 
the tliird assumed to be equal to one of the others. For exainple, 
in the case of the petal epidermis the average dimension (8 . 7), 
nieasured parallel to the surface of the petal as seen in the longi- 
tudinal section is called “lengtlf’, the average dimension (14 . 8) per- 
pendicular to the surface is called “width”; and the third dimension 
is held to be 8 . 7, because in surface view epidermal cells are 
nsually approximately isodiametric. The volume of the nuclei was 
obtained by the formula 4 / 3 — r 3 , the diameter of each nucleus being 
obtained as the average of two measurements at right angles to each 
other. Usually the nuclei are nearly spherical, so that the results 
for the nuclei are probably more accurate than for the cells, which 
are not usually exactly rectangular. In the case of the pollen 
Table II. 
Relative volumes of cells, Lamarcliiana : Gigas. 
Computed from Table I. 
Petal epidermis 1 : 1.96 
Stigma cells 1 : 3.05 
Anther epidermis 1 : 3.837 
Inner wall cells of anthers 1 : 3.67 
Pollen mother cells during reduction. ... 1 : 1.507 
Pollen mother cells in synapsis 1 : 1.506 
Nuclei in synapsis 1 : 2.16 
Nuclei in synapsis (surface area] 1 : 1.67 
Tapetum (multinucleate, 1 : 1.44 
Table III. 
Increase in dimensions of cells of Gigas , calculated from Table I. 
Length increased 
Width increased 
Petal epidermis 
18.4X 
39.8 % 
Stigma cells 
51.9%- 
32.2 X 
Anther epidermis 
T2.8X 
28.4 X 
Inner wall cells of anther 
57.7 % 
48.06 % 
Pollen mother cells during reduction 
10.9 & 
10.3 % 
Pollen mother cells in synapsis 
4.8X 1 ) 
25.4 % q 
! This discrepancy probably results from the small number of measurements. 
