454 BOTANICAL GAZETTE [November 



accomplish this specialists have been allowed to concentrate their attention 

 on a limited field of one or two cereals. The importance of practical trials, 

 the use of hybridization, and some of the practical results are noted, as well 

 as the fact that mutations do appear in cultivated plants; but the main point 

 of the paper is the contribution made to the science of plant breeding by the 

 method of pedigree culture originated at the Svalof station. — Geo. D. Fuller. 



The case of Oenothera. — Probably no genus of plants has ever been the 

 subject and the cause of so much investigation as Oenothera. It has become 

 a storm center, and it is to be hoped that the result will be the clearing of an 

 atmosphere which has become heavy with discussion. The latest contribu- 

 tion to this field of controversy is by Shull,3 w ho suggests that Oenothera 

 itself may be the occasion of the trouble, since "fundamental difficulties are 

 encountered whenever attempts are made to apply to the Oenotheras rules of 

 genetic behavior which are readily demonstrated in other groups of organisms." 

 He concludes, for example, that Oenothera must have a hereditary mechanism 

 fundamentally different from that which distributes the Mendelian unit char- 

 acters. 



In connection with the results of breeding experiments reported on in the 

 present contribution, Shull is convinced that certain conclusions reached by 

 Gates regarding the origin and genetic nature of the rubricalyx character are 

 erroneous, a character which the former has found behaving in various per- 

 plexing ways. The conclusions objected to are that the character represents 

 a purely quantitative difference from O. rubrinervis; that it differs from the 

 latter species in a single monohybrid Mendelian unit; and that the nature of a 

 character itself, instead of the nature of the inheriting-mechanism to which 

 it is related, determines the manner of inheritance of that character. — J. M. C. 



Chromosomes and sex. — Doncaster 10 has continued his breeding experi- 



inheritance 



In a previous 



paper he had described a strain which in each generation produced females only 

 and showed that the oogonia of this strain had 55 chromosomes instead of 56, 

 the normal number in the species. The more recent studies confirm the re- 

 sults previously announced and add further interesting data. It is found that 

 the tendency to produce only females " varies in intensity/' ranging from 

 equality of the sexes to complete absence of males. It was discovered that 

 the eggs of females with 55 chromosomes in the oogonia have 28 in one polar 

 equatorial plate and 27 in the other. The facts as a whole make it clear that 

 eggs which eliminate the 28th chromosome produce females, while those which 



ARRISON 



Jour. Genetics 4:83-102. pis. 5, 6. 1914. 



« 



10 Doncaster, L., On the relations between chromosomes, sex-limited transmis- 

 sion, and sex-determination in Abraxas gross ular lata. Jour. Genetics 4 : 1-2 1. pis- i~3 

 1914. 



