No. 2, September, 1920] GENETICS 221 



1669. Sturtevant, Robert S. Hybridizing bearded irises. Clard. Chron. 67: 184. 

 April 10, 1920. — Refers to a number of crosses of horticultural varieties and presents evidence 

 to show that plicala characters are not due to a recessive factor as proposed by Bliss [see 

 Bot. Absts. 5, Entry 1460]; also indicates thai in I he Iris, venation acts as a simple Mendelian 

 dominant but that in regard to color and its disposition in other ways a more complex expla- 

 nation is needed. — J. Marion Shull. 



1670. Sumner, Francis B. Geographic variation and Mendelian inheritance. Jour. Exp. 

 Zool. 30: 369-402. 7 fig. April 5, 1920.— Paper is continuation of earlier biometric and genetic 

 work on geographic races of deer-mouse (Peromyscus maniculatus) found in California. 

 Characters chosen for study were length of tail, foot, ear, pelvis, femur and skull, width of 

 dorsal tail stripe, color of pelage, pigmentation of foot and number of caudal vertebrae. Fewer 

 grades for any one character have been found than number of localities from which material 

 was collected. Members of same subspecies collected from different localities often differ 

 widely. To a certain extent and for certain characters gradations considered follow geograph- 

 ic and climatic sequence. Degrees of difference in characters are, however, not propor- 

 tional to geographic intervals between races and there are other incongruities which greatly 

 complicate the situation. Characters which vary together, when geographic sequence is 

 considered, may or may not vary together within any single local collection and vice versa. 

 It seems that special factors, operating locally, must be responsible for modification of parts 

 which do not ordinarily vary together. Animals from coastal stations, which probably pre- 

 sent graded series in respect to both temperature and humidity, show similar gradation in 

 respect to mean width of tail stripe and mean length of tail, foot and ear. Suggestion is made 

 that environment in course of time has modified characters of animals dwelling at various 

 points. Variations within each race are partly hereditary and partly 'somatic' in origin. 

 Differences between local races do not act, in crossing, as simple Mendelian factors although 

 theory of multiple factors would undoubtedly be invoked by many geneticists. Author pre- 

 fers theory of contamination of genes. Deviations from type of various characters in F t 

 and F 2 generations have been compared. Conclusion is made that variation is slightly greater 

 in F s . Incidentally differences have been observed between sexes, viz., smaller feet and larger 

 pelvis in females. These are attributed to presence of at least two hormones varying inde- 

 pendently.— P. W. Whiting. 



1671. Sutton, Arthur W. Brassica crosses. Card. Chron. 67: 20. Jan. 10, 1920.— 

 Issue is taken with the statements of a writer in a recent issue of the journal in regard to crosses 

 between cauliflower and kohl-rabi. Cauliflower crosses readily with any other type of Bras- 

 sica but the resulting forms are worthless. — C. B. Hutchison. 



1672. Tammes, T. De leer der erffactoren en hare toepassing op den mensch. Rede, uit- 

 gesproken bij het aanvaarden van het ambt van buitengewoon hoogleeraar aan de Rijks-Univ. te 

 Groningen. [The theory of hereditary factors and its applicability to man. Address, delivered 

 on assumption of the office of Professor Extraordinarius in the State University at Groningen.] 

 H/f. p. Wolters: Groningen., 1919. 



1673. Th., G. Systematic breeding. Florists' Exchange 49: 882. April 10, 1920.— Popu- 

 lar account of the value of systematic breeding based on a knowledge of the laws of heredity, 

 especially as applied to carnation breeding. Lack of such knowledge may result in an occa- 

 sional striking prize in commercial breeding, but no continuous series of successes. Describes 

 some work of carnation breeders. — Dorner & Sons, Ward, and Fisher. Systematic breed- 

 ing in the hands of these men brought the five-inch carnation and many other improve- 

 ments. Dorner & Sons' promising new carnation productions are tested out by Samuel 

 Goddard, Framingham, Mass. Carnation breeding is toward better keeping qualities, better 

 form and color, larger number of blooms per plant without decrease in flower size and produc- 

 tion of a good yellow type. — Orland E. White. 



1674. Th., G. Systematic breeding organization proposed. Florists' Exchange 49: 1089. 

 May 8, 1920.— Discussion of the advantages of systematic breeding and of the formation of a 



