,")!lti Lutz, Triploid Mutants in Oenothera. 



The petals were a slightly deeper yellow than is typical of the 

 parental form (this appearance possibly being due to increased 

 thickness of the petals), and the flowers resisted the effect of the 

 morning sunlight a little longer than 0. lata. 



The anthers had much the same appearance as those of the 

 parental form, and but very little pollen was exposed. However, 

 by pursuing the same methods as those which will be later described 

 for the fertilization of 0. lata, enough pollen was secured to thor- 

 oughly cover the stigmas of 3 or 4 flowers. But 4 seeds were obtained, 

 all of which failed to germinate. 



From studies of root-tips from this plant the somatic chromosome 

 number was found to be 22. Many beautiful figures were observed 

 in which the chromosomes were well separated and clearly defined, 

 leaving no question whatever as to the certainty of the count. 



The nature of the vegetative characters and the somatic 

 chromosome numbers of the offspring of the mutants above described 

 become a subject of great interest and importance. Dr. Shull 

 has kindly given me permission to quote from his descriptions of 

 these forms in the early rosette stage (May 12, 1911). 



Offspring of 1910 21-chromosome mutants (first form described 

 in this report: 



5445 self-fertilized (described above as No. 3, culture 6046) 

 "produced only 3 plants, no t\vo of which are alike; one conforms 

 to the 5509 13 ) type, and another resembles linear-leafed gigas with 

 lanceolate, acute leaves, not crinkled, but with margins strongly 

 undulate. The third also resembles gigas in some ways, but with 

 broad, uncrjnkled leaves." 



5483, self-pollinated (one of the three individuals described 

 above as No. 4, culture 6048), "has given me a family of 77, all 

 but 2 of which are apparently good 0. Lamarrkiana. These 2 have 

 round crinkled leaves resembling (). lata, tho a little darker green 

 and having a heavier texture than usually seen in that form." 



5558, self- pollinated (described as No. 5, culture 6051), "produced 

 8 offspring, 3 of which were albida, 1 lata and 1 having broad 

 heavy leaves with winged petioles, grayish pubescent, somewhat 

 resembling 0. gigas. One other had long, lanceolate, sharp pointed, 

 shining, darker green leaves, thick and leathery. The other two 

 are too young to describe at present." 



13) 5509 represented a type of mutant frequently appearing among the cultures 

 of 0. Lamarckiana at Cold Spring Harbor which was thought to have many 

 characters corresponding to de Vries' descriptions of (t. oblonyn. The frequency 

 of its appearance seemed a further indication of its identity, but Professor de Vries 

 has recently stated to me that so far as he could judge from photographs and 

 descriptions, this form did not appear to be oblonga. 



