328 GENETICS [Bot. Absts. 



Fi plants segregated into blue and yellow in the ratio 3:1. Considering flower color and an- 

 ther color simultaneously 4 classes appear: dark flowers, blue anthers; dark flowers, yellow 

 anthers; pale flowers, blue anthers; pale flowers, yellow anthers, in a ratio close to 9: 3: 3: 1. 

 The gene for dark flower color and the gene for blue anther color are not linked. Anther 

 color and throat color are conditioned by the same gene. — E. B. Babcock. 



2182. Rasmuson, H. Zur Frage von der Entstehungsweise der roten Zuckerruben. [On 

 the origin of red sugar beets.] Bot. Notiser 1919: 169-180. 2 fig. 1919. — Some red sugar 

 beets were planted in a place where no pollination by other sorts could occur. Four of these 

 plants gave together 456 red, 182 yellow and 201 white ones. These numbers indicate, as also 

 shown by Kajanus, the segregation 9:3:4. Some of the plants produced had appearance of 

 fodder beets. The red plants had a smaller content of sugar than the white ones in the 

 same parcel. Among the offspring of the red plants there was great variation (6-16.8 per cent) 

 in amount of sugar, undoubtedly due to genotypical differences, consequently fodder-beets 

 were segregated as to all qualities analyzed. Probably the original red sugar beets were Fi 

 plants from the combination, sugar beet X fodder beet. — K. V. Ossian Dahlgren. 



2183. Renner, O. [Rev. of: Batjr, E. Mutationen von Antirrhinum majus. (Muta- 

 tions of Antirrhinum majus). Zeitschr. indukt. Abstamm. Vererb. 19: 177-193. 10 fig. 

 June, 1918. (See Bot. Absts. 2, Entry 1198.)] Zeitschr. Bot. 11: 212-214. 1919. 



2184. Renner, O. [Rev. of : (1) Haecker, V. Entwicklungsgeschichtliche Eigenschafts- 

 analyse (Phanogenetik). Gemeinsame Aufgaben der Entwicklungsgeschichte, Vererbungs- 

 und Rassenlehre. (Developmental analysis of characters, (Phaenogenetics.) General problems 

 of development, heredity and eugenics.) x + 844 V-> 1&1 f-9- Gustav Fischer: Jena, 1918. 

 (See Bot. Absts. 1, Entry 1216.)] (2) Idem. Entwicklungsgeschichtliche Vererbungsregel. 

 (Embryological analysis of characters or of races.) Zeitschr. indukt. Abstamm. Vererb. 

 14:260-280. 1915. (3) Idem. Uber eine entwicklungsgeschichtliche Vererbungsregel. (On 

 an embryological rule of heredity.) Zeitschr. indukt. Abstamm. Vererb. 18: 1-21. 1917.] 

 Zeitschr. Bot. 11:201-205. 1919. 



2185. Roberts, H. F. Darwin's contribution to the knowledge of hybridization. Amer. 

 Nat. 53:535-554. Nov -Dec, 1919. — Darwin observed that crossability is not determined 

 by systematic affinity, and noted the differential facility of making reciprocal crosses, (which 

 he compares with. differential success of reciprocal grafts), and the differential fertility of 

 hybrids produced thereby; but the degree of facility of crossing is no measure of fertility of 

 hybrid produced. He was surprisingly familiar with facts of self-sterility and felt that the 

 problem was far from solved. He clearly visualized hybrid vigor (height and weight) as 

 proportional to degree of difference (not necessarily external differences) between parents of 

 the cross, whether or not they had been crossed or selfed during previous generations. He 

 observed increased resistance and earlier flowering of hybrids and explained them as due to 

 the fact that forms used in the cross had been exposed to different conditions, bringing a 

 differentiation in their sexual elements (he thought this explained self-sterility also), and 

 claimed to have proved that if such differentiation had not taken place the different flowers 

 on the same plant did not bring vigor, even when these flowers differed in appearance. Rela- 

 tive weight of seeds produced by a cross and a selfing was 100: 96; relative germinating 

 ability was dubious. In crosses among 57 species of 52 genera, relative height of hybrids to 

 inbreds was as 100: 86. Hybrid vigor was transmitted to F2, and was sometimes accom- 

 panied by decreased fertility. He was not much interested in transmission of characters to 

 hybrids and says that intermediacy is the usual thing, sometimes "prepotency," and "some 

 characters refuse to blend." He got in F 2 a ratio of 88: 37 but did net visualize 3: 1. Pre- 

 potency "sometimes depends on the same character being present and visible in one parent 

 and latent or potentially present in the other. "Reversion was the coming to light of a latent 

 character." "The elements of both parent species exist in every hybrid in a double state, 

 namely, blended together and completely separated." "When two hybrids pair, the com- 

 bination of pure gemmules derived from the one hybrid with the pure gemmules of the same 



