No. 2, June, 1921] GENETICS , 153 



potencies. Evidence is summarized that sex differentiation in monoecious and hermaph- 

 rodite flowering plants is likewise independent of special genetic determiners of sex, 

 that here maleness and femaleness resides equally in the most differentiated of sex organs, 

 and that sex differentiation is here purely a phenotypic development. — A. B. Stout. 



1067. CoRRENS, C. Individuen und Individualstoffe. [Individuals and individual sub- 

 stances.] Ber. Senckenberg. Naturf. Ges. Frankfurt a. M. 47: 65-66. 1919. 



1068. CoRRENS, C. Vererbungsversuche mit buntblattrigen Sippen. III. Veronica gen- 

 tianoides albocincta. IV. Die albomannorata- und albopulverea-Sippen. V. Mercurialis annua 

 versicolor und xantha. [Genetical studies with variegated races. III. Veronica gentianoides 

 albocincta. IV. The albomannorata and albopulverea races. V. Mercurialis annua versicolor 

 and xantha.] Sitzungsber. Preuss. Akad. Wiss. Berlin 6, 7: 212-240. 1920.— III. Veronica 

 gentianoides albocincta. This race of Veronica appears to be a case of a real white-margined 

 type of variegation. It is self-sterile. When crossed with normal green plants {tijpica) 

 nothing but green plants appeared in Fi and F2, indicating no inheritance of this variegated 

 character. IV. Albomarmorata and albopulverea races. Both show a white-green spotting or 

 mosaic that is inherited similarly. The spotting of albopulverea is much finer than that of 

 albomarmorata. 1. Ipomoea imperialis chlorina and albomarmorata. The following types 

 were isolated from commercial seed and their genetic constitution determined: a. Normal 

 green {typica homogenea), CCN N HH. h. Pale green {chlorina homogenea), CCnnHH. 

 c. White-spotted green {typica albomarmorata), CCNNhh. d. White-spotted pale green 

 {chlorina albomarmorata), CCnnhh. Factor C produces the chlorina pigment; factor iV 

 changes chlorina to normal green; and factor H produces solid leaf color as contrasted with 

 the spotted condition. The latter factor is inherited independently of C and IS! . 2. Tro- 

 paeolum majus chlorinum and albopulvereum. These 2 races of Tropaeolum are similar to 

 those of Ipomoea noted above. The chlorinum type is given the genetic formula CCnnHH 

 and the albopulvereum type, either CCNNhh {typica) or CCnnhh {chlorina). V. Mer- 

 curialis annua versicolor and xantha. The versicolor race produces seedlings that begin with 

 yellow leaves which later become green permitting the plant to survive. This character is 

 found to be a simple Mendelian recessive to normal green. In the xantha race the seed- 

 lings are yellow and remain so, the plant eventually dying. Duplicate factors are con- 

 cerned in the inheritance, giving both 15:1 and 3:1 ratios of green to yellow seedlings. — 

 E. W. Lindstrom. 



1069. CosTANTiN, J. Physiologic de Tanthocyane et chimie de la chlorophylle. [Physi- 

 ology of anthocyan and chemistry of chlorophyll.] Ann. Sci. Nat. Bot. X, 1: xxxviii-lii. 1919. 

 — See Bot. Absts. 7, Entry 411. 



1070. CowGiLL, H. B. Cross-pollination of sugar cane. Sugar 21:580-581. 1919. — 

 Methods used in cross-pollination of sugar cane. — C. W. Edgerton. 



1071. Davenport, C. B. Influence of the male on the production of twins. Med. Rec. 

 1920: 1-10. 1920.— "About 1 per cent of all human births are plural births." Some mothers 

 have more than one pair of twins and may be called "repeaters." Such women may be con- 

 sidered to have a constitutional "ovarial structure that readily permits double ovulation," 

 and such structure is conceivably inheritable. Among the "close relatives of repeating 

 mothers" it is found that "the ratio of twin production rises to 4.5 per cent." But also 

 among the close relatives of fathers of twins it is found that the incidence of twins is as high 

 as 4.2 per cent, hence "the paternal inheritance is real and nearly as potent as the maternal. 

 The problem is to account for this paternal influence. Double ovulation is not universal in 

 women but "is far commoner, proportionately, than twin births." A study of pregnant 

 swine shows that the number of corpora lutea exceeds the number of embryos and the latter 

 exceed the number of births. Fetuses die at all stages from no apparent cause but inherent 

 weakness. These facts are apparent in human pregnancies. — Geneticists now recognize 

 "lethal factors," transmitted according to the laws of heredity, "which brought in by one or 



