MUTATIONS, VARIATIONS, AND RELATIONSHIPS OF THE OENOTHERAS. 63 



the press. Among the large progeny grown from guarded seeds was only one 

 which showed any marked variation from the blunt rounded leaves of the 

 rosette of the derivative, but this variation did not extend to the foliar organs 

 developed later. 



The radium pencils which were later used on 0. lamarckiana were affixed to 

 an inflorescence in such a manner that the radium coatings were 15 to 25 mm. 

 from developing flower-buds. The corollas of many were so retarded that 

 they failed to open and fell off prematurely. At greater distances develop- 

 ment of the ovary proceeded but slowly and normal size was not reached. 

 Perfect seeds were formed in many of them, however, and these when sown 

 gave the normal frequency of the aberrant mentioned above, and which is not 

 to be confused with the one induced by the stimulative action of zinc sulphate. 



Some decisive results were also obtained from Raimannia odorata, a member 

 of a separate genus of the evening-primrose family from Patagonia. During 

 the first season (1905) injections of the ovaries were made with several sub- 

 stances, with the result that an atypic form identical in all cases was found in 

 seeds from ovules that had been treated in various ways. Two such mutants 

 were secured from seeds of an ovary that had been treated with a 10 per cent 

 sugar solution, 10 from one that had been injected with a solution of calcium 

 nitrate i part to 1000 of distilled water, and one was also found in the 

 progeny from seeds taken from a capsule which had been exposed to the 

 action of a radium pencil. 



In all of these injections ordinary jointed metal syringes were used, and the 

 water was from a single distillation in a copper still, so that no special reliance 

 may be placed upon the purity of the solution injected into the ovary. 



Seeds from capsules which had been treated were harvested in June, 1905, 

 and were sown early in July. The atypic derivatives could be recognized as 

 soon as the cotyledons were fully expanded, and no skill was needed for their 

 detection. The parental form bore leaves villous hairy, or with ciliate mar- 

 gins, while the mutant was entirely and absolutely glabrous. The leaves of 

 the parent generally have an unbalanced linear growth of the margins by 

 which the blades become fluted. The excess of growth in the mutant lies 

 along the midrib and the margins become re volute. The leaves of the mutant 

 show much less expansion than those of the parent, the lower ones being 

 narrowly linear, 5 to 6 cm. long and 3 to 4 mm. wide, while the upper ones are 

 lanceolate linear, 3 to 4 cm. long or even longer, the mutant being much the 

 narrower. The parental type is of a marked biennial habit and near the close 

 of the season the internodes formed are extremely short, which results in a 

 dense rosette. The mutant does not make a rosette, by reason of the fact 

 that its stem does not alter its rate of elongation, but proceeds at a uniformly 

 rapid rate, thus presenting a leaf-stem which appears to be perennial in the 

 climate in which the experiments were performed. So rapidly did develop- 



