February, 1920] GENETICS 41 



282. Kobkrts, H. 1'. Quantitative character-measurements in color crosses. Science 49: 

 516-517. May 30, 1919. — -Writer suggests that in the study of coat pattern in animals, photo- 

 graphs be taken of the right and left sides and the areas determined by planimeter, ruled 

 squares on the photographic plate, or by placing the animal behind cross-wire screen before 

 taking photograph. — Sewall Wright. 



283. Roberts, Herbert F. The founders of the art of breeding. II. Jour. Heredity 

 10: 147-152. 1 fig. Apr., 1919. 



284. Rosenberc, Otto. Chromosomenzahlen und Chromosomendimensionen in der Gat- 

 tung Crepis. [Chromosome number and chromosome dimensions in the genus Crepis]. Ark. 

 Bot. 15": 1-16. 6 fig. 1918. — The haploid number of chromosomes in species of Crepis is 

 reported as follows: In virens, polymorpha var. stricta; Reuteriana, and dichotoma, 3; in 

 foetida, pulchra, agrestis, parviflora, neglecta, and nicaensis, 4; in multicaulis, rigida, and 

 rubra, 5; in barbata, 9; and in biennis, 20. Previous studies have shown that teclorum and 

 taraxacifolia have the number 4; lanceolata var. platyphyllos, 5; and japonica, 8. — Special 

 studies of size of chromosomes are reported which show that in species with 3 chromosomes 

 (virens and Reuteriana) there is 1 large, 1 middle-sized and 1 small chromosome. A species 

 with 4 chromosomes (C. tectorum) has 1 large, 1 middle-sized and 2 shorter chromosomes. 

 C. rubra has 1 large, 1 middle-sized and 3 short chromosomes. Measurements show that the 

 relative proportions of the different chromosomes are very similar in various species as for 

 example: 



abed 



C. tectorium 10 : 7.9 : 5.9 : 5.3 



C. Reuteriana 10 : 7.4 : 5.7 



Heterotypic divisions show evidences of irregular distribution of chromosomes. The 

 short chromosomes especially tend to go to the wrong pole or to lag and be left behind. In 

 Reuteriana about 30 per cent of the divisions show such a tendency, which it is considered may 

 give microspores and macrospores of 3 and 2 chromosomes. In a species with 4 chromo- 

 somes, as C. tectorium, when a short chromosome goes to the wrong pole spores with 5 (1 

 large, 1 middle-sized, 3 small) chromosomes and spores with 3 (1 large, 1 middle-sized, 1 short) 

 chromosomes would be formed. 



Conclusion is that the 3, 4 and 5 series of chromosome numbers in species of Crepis arises 

 through irregular distribution of the smaller chromosomes in reduction divisions and subse- 

 quent recombination in fertilization rather than through segmentation or fragmentation of 

 the larger chromosomes. — A. B. Stout. 



285. Sakamura, Tetsu. Kurze Mitteilung iiber die Chromosomenzahlen und die Ver- 

 wandtschaftsverhaltnisse der Triticum-Arten. [Chromosome number, etc., in Triticum.] 

 Bot. Mag. Tokyo 32: 151-154. 1918. — From studies on root tips and on pollen mother cells 

 author obtained diploid chromosome counts on races of wheat as follows, — Triticum vulgare 

 42, T. compactum 42, T. spelta 42, T. turgidum 28, T. durum.28, T. polonicum 28, T. dicoccum 

 28, T. monococcum 14. This contrasts with haploid counts by Overton, Nakoa, Bally and Dud- 

 ley of 8 chromosomes for T. vulgare and of Kornicke's haploid count of 8 chromosomes for T. 

 compactum. Author concludes that the primitive chromosome numbers in Triticum species 

 were haploid 7, diploid 14, and that the diploid chromosome number holds the following 

 relation to Schulz's grouping, — Einkornreihe, diploid, 14 chromosomes {T. monococcum); 

 Emmerreihe, tetraploid, 28 chromosomes (T. dicoccum, durum, polonicum, turgidum); Dinkel- 

 reihe, hexaploid, 42 chromosomes (T. compactum, spelt, vulgare). The chromosome count of 

 rye, Secale cereale, is reported as haploid 7, diploid 14. — B. M. Davis. 



286. Salmon, C. E. Papaver Rhaeas, P. dubium and the hybrid between them. New 

 Phytol. 18: 111-117. 7 fig. Mar .-Apr., 1919.— See Bot. Absts. 3, Entry 2187. 



287. Salmon, C. E. A hybrid Stachys. Jour. Linnean Soc, London 44: 357-362. 1 fig. 

 May 16, 1919— See Bot, Absts. 3, Entry 2188. 



BOTANICAL ABSTRACTS, VOL. Ill, NO. 2 



