ABNORMALITIES IN OENOTHEBA. 183 



germinating pots each year. They are particularly common 

 in 0. gigas, jsut no record of them has been kept. 



Vakibgation of Leaves. — Yellowish areas not infre- 

 quently appear on the rosette leaves, particularly in the Eng- 

 lish Oenotheras. One striking case of what was evidently 

 a sectorial chimera according to Baur's (1909) terminology, 

 occurred in a culture of 55 plants very closely resembling 

 0. Lamarckiana, but having larger rosettes with rather 

 broader leaves. They constituted the second pure generation 

 from seeds of a plant near Liverpool, England. The green 

 areas on the leaves in this plant are contrasted with areas 

 which are yellowish white, showing a complete absence of 

 chloroplasts. It will be seen that in several leaves the line be- 

 tween white and green tissue passes down the midrib, while 

 one or two leaves exhibit patches of white adjoining the mid- 

 rib. Plate 31, from a photograph taken June 30, 1909, shows 

 the partly developed rosette. The leaves arising from one side 

 of the stem are wholly white, those on the opposite side are 

 mostly pure green, while several others are green on one- 

 half and white on the other. A few areas of pale green, 

 owing to partial absence of chlorophyll, were also observed. 

 The white areas were of course unable to nourish themselves, 

 and continually died away. The plant never formed a shoot, 

 but died before the end of summer, notwithstanding the most 

 careful treatment. The plants of the previous generation 

 gave no indication of such a condition, which therefore ap- 

 peared suddenly in this individual, and appeared, moreover, 

 from a seed of a plant which was normal green throughout. 

 Presumably one side of the young growing point was without 

 chloroplasts, but just how this condition came about is at 

 present a matter of conjecture. 



