126 GENETICS [Bot. Absts., Vol. IV, 



tent life. — There is also need of critical experiments concerning origin of inherited variations. 

 Discrepancy between Lotsy's recent statement, "of heredity we know nothing," and Mor- 

 gan's conclusion, "The problem of heredity may be said to be solved," results from different 

 view points. Former had in mind complex potentialities of germ cell, the latter merely the 

 method of character distribution. Author distinguishes between apparent failure of an 

 organism to inherit individually acquired body characters and the possibility of inheriting 

 individual experiences. Results of Castle's experiments with hooded rats and Illinois experi- 

 ments on protein content of corn (maize) will eventually be better understood [prophecy ful- 

 filled]. Evolution of selected and of selection processes go hand in hand.— L. B. Walton. 



785. Thompson-, W. P. The inheritance of the length of the flowering and ripening periods 

 in wheat. Proc. Trans. Roy. Soc. Canada 3 : 69-S7. 1918. — Reports results of crosses between 

 many pairs of wheat varieties differing by many degrees in regard to length of ripening and 

 heading periods. Crosses were made between parents differing only slightly, also crosses 

 involving greater parental differences. Fi plants matured with late parent. F 2 plants formed 

 regular curves of probability with variation from below mean of lower parent to above mean 

 of higher parent. Sometimes parental extremes were exceeded. Interpreting results on 

 basis of multiple-determiner hypothesis of blending, the sum of the differences between each 

 successive pair of parents seems to be much greater than it should be on the evidence of direct 

 crosses. Hypothesis, therefore, fails to explain satisfactorily the results as a whole though 

 it may explain satisfactorily the results of each individual cross. — E. A. Southee. 



786. Thomson, J. Arthur. [French rev. of: Downing, E. R. The third and fourth gen- 

 eration. An introduction to heredity, xi+164 p., 13 fig. Univ. Chicago Press: Chicago, 

 1918.] Scientia 27: 72-74. Jan., 1920. 



787. Thomson, J. Arthur. [French rev. of: Morgan, T. H., A. H. Sturtevant, H. J. 

 Muller, and C. B. Bridges. The mechanism of Mendelian heredity, xii+262 p., 64 fig. 

 A. Constable & Co.: London. 1915.] Scientia 27: 74-75. Jan., 1920. 



788. Tischler, G. Untersuchungen iiber den anatomischen Bau der Staub- und Frucht- 

 blatter bei Lythrum Salicaria mit Beziehung auf das Illegitimitatsproblem. [Studies of the 

 anatomical structure of the stamens and carpels in Lythrum Salicaria with reference to the 

 problem of illegitimacy.] Flora 11, 12 (Festschrift Stahl) : 162-192. 1918.— Haploid number of 

 chromosomes of Lythrum salicaria is almost certainly 24, diploid 48. Chromosomes are un- 

 equal in size, which in different flowers is considered due to nutrition. Genotypical differences 

 of heterostyled plants are not correlated with chromosome size. Nuclei of mature pollen grains 

 of heterostyled individuals having same chromosome number are apparently of same size, con- 

 sequently the cell contents differ very much in amount since the pollen of the smallest and 

 medium-sized stamens is contrasted with that from the largest in size. Characteristic size 

 variations of the cells of the heterostyled plants are also shown in ovules, ovarian tissue, and 

 in stigmas. Muller's generally accepted statement that the stigmatic papillae show typical 

 differences is not confirmed. Short-styled flowers have larger papillae than medium or long- 

 styled. Relatively small number of measurements of stigmatic papillae from plants with 

 different flower forms give a normal curve with no suggestion of three modes. The size of the 

 stigmatic papillae and also the papillate epidermal cells of Lythrum vary with the nutrition, 

 corresponding with the supply of water and other materials. A parallel exists between hetero- 

 styly and dioecism. Within the same families or even the same genera, as for example, Lyth- 

 racae, Oxalidacae, Rubiacae, Caryophyllacae, Primulacae and Polygonadae, heterostyly and 



Oogamy occur together while heterostyly and dioecism are seldom found associated. A 

 morphological adaptation of the pollen grains to particular styles or stigmas does not exist 

 Only to chemical agency can tin' partial but not absolute self-sterility of Lythrum salicaria 

 ibuted. [See also Bot. Absts. 4, Entry 815.] — D. E. Jones. 



789. TlBCHLBB, G. Analytische und experimentelle Studien zum Heterostylie-Problem 

 bei Primula. [Analytical and experimental studies on the problem of heterostyly in Primula.] 



