No. 2, September, 1920] GENETICS 211 



1601. Pammkl, L. H., andC. M. King. A variation in the black walnut. Proc. Iowa Acad. 

 Sci. 25: 241-248. PI. 3, fig. 43-44. 1920. 



1602. Patterson, J. T. Polyembryony and sex. Jour. Heredity 10: 344-352. 2 fig. 

 Nov., 1919. 



1603. Pellew, Caroline. The genetics of Campanula carpatica. Card. Chron. 66: 

 23S. S fig. Nov. S, 1919. — A brief consideration of investigations of the author more com- 

 pletely discussed in "Types of segregation," Jour. Genetics 6: 1917. — In Campanula carpatica 

 hermaphrodites occur with male and female organs fully developed. In other plants the an- 

 thers fail to develop beyond a rudimentary stage while in others, still, development of the 

 anthers is partial. Self-sterility is general in this species. In certain strains of C. carpatica 

 pelviformis crosses between hermaphrodites or between females and hermaphrodites inva- 

 riably gave mixed families consisting both of females and hermaphrodites, often with a pre- 

 ponderance of females. The hermaphrodites appear to produce more gametes carrying the 

 female character than gametes carrying the hermaphrodite character. There is no consistent 

 difference in this respect between the ovules and pollen of a single plant. In other strains 

 the pollen and ovules differ. Two hermaphrodites were found, pollen of which, when used 

 on females, gave rise exclusively to females, whereas ovules of the same plant fertilized by 

 other hermaphrodites gave rise exclusively to hermaphrodites. A flower-color factor pair 

 in this species also follows this unusual type of segregation by which the ovules and pollen 

 are differentiated. Normal segregation of the color factor occurs on the female side result- 

 ing in equal numbers of ovules bearing blue or white allelomorphs. Ninety-seven per cent 

 of the pollen grains, however, carry the white allelomorph and three per cent only the blue 

 allelomorph.— Power of transmitting this unusual mode of segregation from parent to off- 

 spring is apparently limited to the ovules, for no plant similar to C. carpatica pelviformis 

 has been derived from its male side. This type of segregation may be compared with the 

 double-throwing variety of stock. — C. B. Hutchison. 



1604. Pezard, A. Castration alimentaire chez les coqs soumis au regime came exclusif. 

 [Alimentary castration in a cock subjected to an exclusive meat diet.] Compt. Rend. Acad. 

 Sci. Paris 169: 1177-1179. 1919. 



1605. Pitt, Frances. Notes on the inheritance of color and markings in pedigree Here- 

 ford cattle. Jour. Genetics 9: 281-302. 4 pi- Feb., 1920. — Notes and photographs on which 

 this paper is based come chiefly from the breeding of pure bred Herefords owned by W. J. 

 Pitt. — Excessive white on the sides of the belly and down the spine behaved to well marked 

 animals as a recessive factor. The ratios were: heterozygote to heterozygote, 25 well marked: 

 10 excessive white; heterozygote to pure dominant well marked, 52 well marked; heterozygote 

 to recessive excessive white, 7 well marked to 9 excessive white. — Dark neck or extension of 

 the pigment area to include the neck, the crest, and to encroach on the white area on the tail 

 behaved nearly as a dominant to the desired white markings. In the presence of the factor 

 for excessive white the "dark-necked" factor apparently may be inhibited in its action. — A 

 ring of red around the eyes is dependent on a single dominant factor. The ratios for hetero- 

 zygote X heterozygote were 42 red-eyed to 12 white-eyed. The mating of the heterozygote X 

 the recessive white-eyed gave 12 heterozygote to 15 complete recessive. It appears that the 

 factor for red pigment around the eyes is independent of the other factors.— Pigment on the 

 nose behaves as a dominant to clean nose, pigmented X non-pigmented giving 4 pigmented in 

 Fi; pigmented heterozgyous X non-pigmented, giving 3 pigmented to 3 not pigmented in the 

 Fi. — Two pigment factors control coat color. Pale brown coat is dominant over the deep 

 rich purple or claret coat. The factors for coat color apparently behave independently of 

 the rest save with the possible exception of the pigmented nose.— The observation is made 

 that the "claref'-coated animals may not feed as rapidly as the pale brown. — The history of 

 the breed is cited to show that the factors discussed were present in early times. — John W. 

 Go wen. 



