I 



AGRICULTURAL BOTANY. 329 



oration, as a result of his own experiments in hybridizing a number of species 

 cf Cistus he considers that these conclusions are not confirmed. 



Two species derived from a hybrid when crossed with each other do not 

 obey the Mendelian law of dominance, G. Rellair (IV. Conf. Intcrnat. 

 G6ii6UquG Paris, Compt. Rend, ct Raps-., 1011, pp. 201-203). — Experiments with 

 some Nicotiana hybrids are reported which indicate that at least iu this case 

 two species derived from a hybrid when crossed with each other do not obey 

 the Mendelian law of dominance. 



The variability of micro-organisms and the inheritance of acquired char- 

 acters, B. Heinze (IV. Conf. Internat. 06n6tiquG Paris, Compt. Rend, ct Raps., 

 J 911, pp. 278-289). — An account is given of variations that have been observed 

 in different bacteria and fungi. 



Azotobacter was found subject to morphological change under the influence 

 of external conditions, depending upon the stage of development. If the amount 

 of combined carbon was reduced in the media in which pure Azotobacter was 

 cultivated and small quantities of asparagin were given, forms of A. chroococ- 

 cuni and of a blue-green alga appeared which seemed very closely related to the 

 colorless forms of Azotobacter. This would indicate that Azotobacter is not a 

 pure species, but the question is not definitely decided. 



Other examples of the influence of the culture media on algie and on Bacillus 

 prodigiosus and B. cyanogenus are reported. 



Mutations in pure lines of beans, W. Johannsen (IV. Conf. Internat. 

 GcnHlque Paris, Compt. Rend, et Raps., 1911, pp. 160-163). — The author reports 

 the occurrence in pure lines of beans of two mutations. The first appeared in 

 1903 and was immediately constant, while the second appeared in 1907 and was 

 recognized as being in a heterozygous condition. The first was characterized 

 by great size and the relatively narrow shape of the beans, while the second was 

 a broad biotype which could be extracted from the original heterozygote through 

 segregation. 



Grafting- and asexual hybridization, E. Gbiffon (IV. Conf. Internat. G6n6- 

 tique Paris, Compt. Rend, et Raps., 1911, pp. 164-196, figs. 24).^ — Descriptions 

 are given of a number of forms, designated by the author as hybrids, which 

 have occurred as the result of grafting. These include not only annuals and 

 herbaceous perennials, but a number of woody plants as well. 



Notes on parthenogenesis in plants, Rose H. Thomas (IV. Conf. Intcrnat. 

 G6nctique Paris, Compt. Rend, ct Raps., 1911, p. 209). — As a result of her 

 experiments the author has proved that parthenogenesis is possible in several 

 species of Nicotiana and also in the evening primrose and cucumber. Partheno- 

 genetic seeds from these plants were found to reproduce the parental type and 

 the plants were normal and bore fertile anthers. 



Genetic and nongenetic factors in the improvement and breeding of new 

 varieties, A. L. Hagedoorn (lY. Conf. Internat. G6n6tique Paris, Compt. Rend, 

 et Raps., 1911, pp. 132-135). — Attention is called to the genetic and environ- 

 mental factors that influence plant breeding, and the author urges that special 

 care be given to all Fi individuals so that the number of second generation 

 hybrids may be increased as rapidly as possible. He claims that the Fi genera- 

 tion should be especially protected against frost and drought. 



The application of the principles of genetics to some practical problems, 

 C. C. Hurst (77. Conf. Internat. G^n^tique Paris, Compt. Rend, ct Raps., 1911, 

 pp. 210-221). — ^A description is given of the results of hj'bridizing garden peas, 

 sweet peas, orchids, primulas, snapdragons, barberries, forest trees, fruit trees, 

 cabbage, etc. 



A study of abnormal characters in seedlings, with a view to obtaining new 

 varieties, X. Strampelli (IV. Conf. Intcrnat. G^n^tique Paris, Compt. Rend, ct 



