Lutz, Triploid Mutants in Oenothera. 415 



i 



combined with a larger number suggestive of 0. gigas. It is poss- 

 ible, however, that these were true gigas characters, for several 

 plants have since appeared among the pure cultures of 0. giyas 

 at. Cold Spring Harbor which combined many of the common 

 characters of 0. giyas with others that were more suggestive of 

 0. laid. However, to have found a type of gigas having bud- 

 form or crinkledness of leaf (or both) resembling 0. lata does not 

 necessarily indicate that it owes this resemblance to 0. lata 

 parentage, although it does seriously complicate hybridization studies 

 of 0. lata X 0. giyas* 1 }. 



It seems probable, therefore, that the 21 -chromosome plant 

 described by Gates as offspring of 0. lata X 0. giyas, if such, had 

 neither 'almost or quite the identical appearance of 0. gigas', nor 

 vegetative characters 'which appeared to be intermediate between 

 those of 0. lata and 0. gigas', but that it was rather a 21-chromo- 

 some hybrid of the type found common among the Cold Spring 

 Harbor offspring of 0. lata X 0. gigas. The strongest evidence in 

 proof of this assumption is Gates' statement (10) that the 0. lata X 0. 

 gigas hybrid 'matures an abundance of pollen'. Of the hybrids of 

 this cross coming to flower which I have studied, only those having 

 </iyas-[ike characters in combination with a chromosome number in 

 the region of that of 0. gigas, - and the 21-chromosome plants 

 excluding lata characters, produced a moderate abundance of 

 pollen. Those having lata-gigas characters exposed about as little 

 pollen as 0. lata itself. 



It is unfortunate that Gates did not state whether any of 

 the remaining 13 individuals of the supposed culture of 0. lata X 0. 

 Lainarcldana (1) were also derived from seeds of the unguarded 

 seed-package, for the paternal origin of each of the remaining 

 members of this culture are thus left in question, including the 

 so-called " 'mosaic' hybrid". 



It is now well known that 0. lata X 0. Lamarekiana produces 

 the following offspring: 



a) Lata hybrids which are in every way indistinguishable from 

 la fa mutants. 



27) This is but one of the numerous examples which illustrate the fact that the 

 Oenotheras form a most interesting subject for mutation studies, but a much less 

 satisfactory one (with our present knowledge) for hybridization experiments. One 

 may pollinate yellow-budded A, for example, with red-budded B. But A may be 

 capable of throwing red-budded mutants when self-pollinated or crossed with another 

 of its kind, and B, under similar conditions, may throw yellow-budded mutants. 

 Examples of such occurrences will be demonstrated in reports to follow. How is 

 one to know, therefore, that the yellow-budded offspring have derived this character 

 from the female parent, and the red-budded forms the sepal coloration from the 

 male parent? 



