36 GENETICS [Bot. Absts. 



with little differences in the indices of the parents, the children show great divergence of 

 values, or if a single child has a strongly deviating index. Data show great variability and 

 also irregularity of indices. — Proof is presented that headform is not inheritable through a 

 single pair of allelomorphic factors. Data of different families plead for occurrence of 

 plural factors working in the same direction in the sense of Nilsson-Ehle. So e.g., those, 

 where the indices of the children surpass those of the parents in both directions or in one 

 direction. — Dominance may occur as shown by families of which one of the parents and 

 almost all or most of the children are brachycephalic. There are however also families for 

 which this is not the case. Consequently beside segregation simple dominance of brachy- 

 cephaly cannot be admitted. Nilsson-Ehle's scheme of heredity gives the best explanation 

 for the facts. — It is possible that shape of head is complex character and length and width 

 Mendelize separately. There is however correlation of properties and a Mendelian explana- 

 tion of it is given by hypothesis of coupling and repulsion of factors. With absolute coupling 

 the two properties can be represented by one factor of heredity. It is quite possible that for 

 the heredity of shape of head, coupling occurs between factors for length and those for width. 

 This means consequently that in general shape of head can be conceived as one single series 

 of Mendelian characters, but that in some cases deviations will be found, which are the con- 

 sequence of the meeting of gametes of very rare independent factors for length and width. 

 Further investigation of material shows that brachycephalic head-form has not always same 

 behavior in heredity. The brachycephaly may be effect of shortening or of widening of the 

 head. It appears that the brachycephalic, large and wide head is often dominant, while the 

 brachycephalic, small and short head is often recessive to dolichocephalic head-form. It is 

 possible, that for formation of short, small head, the meeting of two factors is necessary. The 

 material given here cannot yet prove this conception. — Broad lines of Mendelism are to be 

 recognized; there are distinct indications of segregation and of independency of factors. 

 With regard to nature and number of the factors of heredity, the phenomena of segregation 

 are too much complicated, to be explained by one pair of factors. Therefore the data are 

 tested by the scheme of heredity of Nilsson-Ehle. — F. P. Fretz. 



252. Freud, Sigmund. Three contributions to the theory of sex. 3d. revised ed., 117 p. 

 Nerv. and Ment. Dis. Pub. Co.: Washington [D. C.]. 1918.— See Bot. Absts. 3, Entry 996. 



253. Harland, S. C. Tomato breeding in St. Vincent. Agric. News, Barbados 17: 4-5. 

 1918— See Bot. Absts. 2, Entry 519. 



254. Harland, S. C. Inheritance of certain characters in the Cowpea (Vigna sinensis). 

 Jour. Genetics 8: 101-132. 1 fig. Apr., 1919— See Bot. Absts. 3, Entry 1003. 



255. Harper, R. A. The evolution of cell types and contact and pressure responses in 

 Pediastrum. Mem. Torrey Bot. Club 17 : 210-240. 27 fig. 1918— See Bot. Absts. 2, Entry 61. 



256. Hastings, G. T. Some abnormal poplar flowers. Torreya 18: 16-18. 4 fig. 1918. 

 —See Bot. Absts. 2, Entry 291. 



257. Hegner, R. W. Heredity, variation, and the appearance of diversities during the 

 vegetative reproduction of Arcella dentata. Genetics 4: 95-150. 27 fig. Mar., 1919. 



258. Hendrickson, A. H. Five years results in plum pollination. Proc. Amer. Soc. Hor- 

 tic. Sci. 15 (1918) : 65-66. 1919— See Bot. Absts. 2, Entry 727; 3, Entry 635. 



259. Holzhausen, A. Laeliocattleya suecica nov. hybr. (LC. Myrra X Pallas). Svensk 

 Bot. Tidskr. Stockholm 13 (part 1): 97-99. 1919. — Author has secured hybrid plants from 

 Callleya remula X C. labiata, C. labiata X C. Mrs. Pitt, ('. Trianaci X C. nobilis and Laelio- 

 cattleya Myrra X LC. Pallas. — The last combination has now flowered and is named Laelio- 

 cattleya suecica. The parents are also hybrids. Laeliocattleya Pallas is Laelia crispa X 

 Cattleya Dowiana and Laeliocattleya Myrra is Laelia Warn X Cattleya Trianaci. A photograph 

 of a flower from the plant in question is reproduced. — A". 1*. Ossian Dahlgren. 



