The Stature and C'hromosouies of Oenothera gigas. De Vries. 541 
unlike and are indeed often indistinguishable except by the repro- 
ductive Organs tbey bear. Tbis is tbe case with tbe genus Polysi- 
pbonia. Yamanouchi, who worked out the life bistory of P. violacea 
(1906) with great detail, and determined the alternation of genera- 
tions, informs me tbat there is no constant difference between tbe 
sporophytic and sexual plants in tbe size of cells or nuclei, although 
one bas 40 chromosomes and the other 20. And I found from Obser- 
vation of species of Polysipbonia at Woods Holl, Mass., tbat tbe 
tetrasporic plants, with 40 chromosomes, are no larger or stouter 
than tbe antheridial or carposporic plants, wbich have 20 chromo- 
somes. Yamanouchi showed that reduction takes place during tetra- 
spore formation, the tetraspores germinating to produce carposporic 
or antheridial plants. Tbe fact tbat there is no difference, either in 
size of cells or of individuals, between tetrasporic and sexual plants, 
shows tbat there is some physiological readjustment without altera- 
tion in tbe kernplasma relation at the two critical phases of fertili- 
zation and reduction. 
Tbis evidence all indicates that a doubling of the chromo- 
somes may or may not be accompanied by an increase in 
tbe size of tbe nuclei and cells. In the case of Polysiphonia 
there is no cbange in tbe size of tbe cells but instead an internal 
physiological readjustment, so that the gametophvtic and sporophytic 
plants are indistinguishable except in the reproductive Organs thev 
bear. In 0. gigas on the other band, in which there is an ext r mal 
change, in the increased size of cells and nuclei, this in itself 
points to the absence of any internal readjustment of 
this sort. 
III. Size of O. gigas. 
0. Gigas is conspicuously larger and stouter in nearly all its parts 
than O. Lamarclciana or any of the other mutants. The leaves are in 
many cases very broad though thev vary widely in shape, and they 
appear to be thicker than in Lamarckiana. The stems are stouter 
and much more thickly covered with leaves, while the internodes are 
shorter and the leaves are more closely pressed against the stem 
(de Vries 1901, I p. 158). The buds and petals are conspicuously 
larger but the capsules are short and thick. The seeds are very 
large. 
The series of measurements tabulated in Table IV, takeu trom 
Mac Dougal 1905 and 1907), give a basis for comparison of the 
Archiv f. Zellforschung. III. 36 
