330 EXPEKIMEKT STATION RECOED. 



Raps., 1911, pp. 237-246, figs. 11). — The author gives an account of experiments 

 with wheat and various species of Leguminosse, the object being to test the 

 value of selecting those seedlings representing abnormalities as a possible 

 means of developing new varieties. 



In the case of wheat, precocity of development was found to be an inherited 

 character, and two forms were obtained which were characterized by marked 

 precocity, short stalk, and stiffness of straw. With alfalfa, clover, and sainfoin, 

 only a small proportion of the descendants possessed the abnormal type. 



The breeding" of double flowers, Edith R. Saunders {IV. Conf. Internat. 

 Genetique Paris, Compt. Rend, et Raps., 1911, pp. 391-405). — In this paper the 

 author deals with a number of practical questions relating to the breeding of 

 double-flowered plants. She distinguishes three types or grades of doubling. 

 In the first the flower becomes so double that neither pollen nor ovules are 

 produced. In the second the organs of only one sex are aborted, while those of 

 the other remain functional. In the third, which is by far the largest class, 

 doubling occurs without loss of function in the reproductive organs of either 

 sex. 



Considering the question of singleness or doubleness, it is stated that single- 

 ness is due to the presence of two factors while doubleness is due to the absence 

 of either or both of them. In the nondoubling single type these factors are 

 linked together, while in the eversporting single type the factors are not linked. 

 All four combinations of the allelomorphs occur among the ovules in an ever- 

 sporting single, but the pollen appears unable to carry the two factors, either 

 alone or together. This is said to be a case of what has been termed partial 

 coupling combined with a sex limited distribution of the factors. 



A popular account of this investigation has been noted elsewhere (E. S. R., 

 29, p. 341). 



Hybrids between species of Antirrhdnum, J. P. Lotsy {IV. Conf. Internat. 

 (Unetique Paris, Compt. Rend, et Raps., 1911, pp. 416-428, figs. 9). — ^A descrip- 

 tion is given of hybrids grown by the author from seeds produced by E. Baur 

 and crossed on a number of species of Antirrhinum. He concludes from his 

 experiments that segregation and the recombination of factors are not limited to 

 hybrids between varieties, but may also occur in hybrids between certain species. 



Mcotiana crosses. Rose H. Thomas {IV. Conf. Internat. Genetique Paris, 

 Compt. Rend, et Raps., 1911, pp. 450-461, figs. 6). — Descriptions are given of a 

 number of Nicotiana hybrids and a detailed account is presented of the differ- 

 ences observed in the pollen grains. 



In most species of Nicotiana the pollen grains are oval and either large or 

 small. In N. tahacum and its allies they are square or approaching that shape, 

 while in N. sylvestris they are round. The segregation of pollen was observed 

 in all the different crosses. 



Experiments in crossing a wild pea from Palestine with commercial peas 

 with the object of tracing any specific identity between this wild pea and 

 peas of commerce, A. W. Sutton {IV. Conf. Internat. Genetique Paris, Compt. 

 Rend, et Raps., 1911, pp. 358-367, figs. 4). — An account is given of experiments 

 in crossing a species of peas obtained in Palestine in 1904 with some cultivated 

 varieties of Pisum sativum to determine if possible whether the first species 

 could be considered the ancestor of some of the cultivated forms. About 40 

 crosses were made between this species and P. sativum and P. arvense, but in 

 only 4 cases were the hybrids carried to the Fs generation, the others being 

 sterile. 



The results obtained can not be considered as demonstrating that the Pales- 

 tine pea was the forerunner of the present garden peas. While some of the 

 hybrids were fertile, yet the character of the flowers, leaflets, and pods, the 



