228 Varietäten, Descendenz, Hybriden. 



sagt in Bull. Jard. bot. Tiflis XII. 2. folgendes über die Varietäten 

 von Alectorolophus maior: Je länger die Entwicklung der Varietät 

 dauert, desto später beginnt sie zu blühen und Früchte anzusetzen; 

 die Schädlichkeit der Entwicklung des Stengels selbst steht 

 auch in bestimmtem Zusammenhange mit der Entwicklungsdauer. 

 V, N. Khitrovo spricht sich in seinen „Kritischen Bemerkungen 

 über die Gattung Geum und ihre Bastarde in der Provinz Orel" 

 so aus: Der Entwicklung jeder Aufbaueinheit der Pflanze entspricht 

 im Räume eine bestimmte Einheit der Zeit, nämlich die Einheit 

 der Wachstumszeit. Matouschek (Wien). 



Lindstrom, E. W., Linkage in Maize: Aleurone and Chloro- 

 phyll factors. (American Naturalist. LI. p. 225—236. 1917.) 



The writers paper has been divided into four parts: Linkage 

 between aleurone and Chlorophyll factors, Determination of the 

 aleurone factor concerned in the linkage, On the question of Cros- 

 sing over in the male and female, Additional Linkages between 

 Chlorophyll factors and aleurone. 



Three factors in genetics of maize are subject of the writers 

 researches: a factor R for aleurone (one out of five factors A, C, 

 R, P, I), described by Emerson, a factor G, one of at least 

 seven factors necessary for the production of füll, normal green 

 color, its allelomorph g producing a distinct yellow or golden 

 in the leaves and stalk of the mature corn plant (Emerson and 

 Miles) and a factor L, one of three factors found by Miles to be 

 responsible for the production of Chlorophyll in the seedling stage 

 of maize. 



The relations obtained between these three factors are: 



Linkage between the R aleurone factor and the G factor for 

 Chlorophyll development shows approximately 20 per cent cross- 

 overs. 



Crossing over takes place in both male and female gameto- 

 genesis of the monoecious maize plant. 



Preliminary tests indicate that G' is also linked with L, the 

 seedling Chlorophyll factor. Consequently the factor pairs Rr, Gg 

 and LI constitute one factorial group in maize. 



M. J. Sirks (Wageningen). 



Pearl, R., The probable error of a Mendelian class fre- 

 quency. (American Naturalist. LI. p. 144—156. 1917.) 



The authors own summary runs as foUows: 



A method is presented of calculating and expressing the 

 errors, due to random sampling, of a Mendelian class frequency. 

 The method consists essentially in expressing each expected 

 Mendelian frequency as the probable quartile limits for that class 

 frequency in a supposed second sample of the same size as the 

 observed sample drawn from the same population. These quartile 

 limits are determined from the ordinates of a hypergeometrical 

 series. Various simplifications of method are suggested and illus- 

 trated. The method is suggested as a Supplement to, not a Substi- 

 tute for, the Xj test for the goodness of fit in Mendelian distributions. 



M. J. Sirks (Wageningen). 



Zinn, J. F. and M. Surface. Studies on oat breeding. V. 



