COBB AND BARTLETT: INHERITANCE IN OENOTHERA 465 



A NEW CASE OF MENDEUAN INHERITANCE IN OENOTHERA. 



Perhaps the most authentic case of MendeHan inheritance in 

 the group of the evening-primroses is that afforded by Oenothera 

 hrevistylis, which acts as a recessive in crosses with its parent 

 species, Oe. Lamarckiana, with other mutations from Oe. 

 Lamar ckiana, and even with unrelated species."** Another in- 

 stance is that of the dwarf mutation from Oe. gigas.'^ Both of these 

 cases have been discovered by de Vries. Heribert-Nilsson^° has 

 presented an elaborate MendeHan explanation of Oenothera 

 genetics which is chiefly remarkable for its failure to square with 

 the facts. It is based upon a supposed monohybrid segregation 

 in crosses between red- and white-nerved races of Oe. Lamarcki- 

 ana. He failed to find dominant homozygotes, and the evidence 

 of MendeHan behavior is anything but clear. Gates ^^ has argued 

 that Oenothera ruhricalyx acts as a MendeHan dominant in 

 crosses with Oe. ruhrinervis, but the question is in controversy 

 between Gates and ShulP- and cannot for the present be re- 

 garded as settled. It is obvious that the whole subject of Men- 

 deHan inheritance in Oenothera needs further investigation. 



Our data deal with the crosses of mnt. formosa E, pollinated by 

 two of the flat-leaved mutations of the C strain. The former is 

 the most fertile and vigorous of the re volute-leaved mutations. 



" DE Vries, Hugo. Die Mutations-Theorie. i: 223; 2: 151-179, 429. 

 * Davis, B. M. The segregation of Oenothera brevistylis from crosses with Oe. 

 Lamarckiana. Genetics 3: 501-533. 1918. 



'■' DE Vries, Hugo. Oenothera gigas nanella, a MendeHan mutant. Bot. Gaz. 



60: 337-345- 1915- 



'" Heribert-Nilsson, N. Die Variabilitdt der Oenothera Lamarckiana und das 

 Problem der Mutation. Zeitschr. fiir ind. Abst. Vererb. 8: 89-231. 1912. 



Heribert-Nilsson, N. Die Spaltungsercheinungen der Oenothera Lamarckiana. 

 Lunds Universitets Arsskrift. N. F., Avd. 2, 12: no. i. pp. 132. 1915. 



'1 Gates, R. R. The mutation factor in evolution. London, 1915. (Gives 

 full references to the original papers dealing with Oenothera ruhricalyx.) 



^^ Shull, G. H. a peculiar negative correlation in Oenothera hybrids. Journ. 

 Genet. 4: 83-102. 1914. 



Gates, R. R. On the origin and behavior of Oenothera rubricalyx. Journ. 

 Genet. 4: 353-360. 1915. 



Gates, R.R. On successive duplicate mutations. Biol. Bull. 29: 204-220. 1915. 



