AGRICULTURAL BOTANY. 29 



13 (1918), No. 1-2 pp. J^l-Sl, figs. 2). — Figures and a description are given of 

 a convenient and cleanly device for obtaining mud and similar material in bot- 

 tles for the study of the contained life forms. 



Studies in Indian tobaccos. — III, The inheritance of characters in Nico- 

 tiana tabacum, Gabbielle L. C. Howard {Mem. Dept. Agr. India, Bot. Ser., 

 6 {1913), No. 3, pp. 25-114, pls. 25, fig. l).—ln a previous paper (E. S. R., 23, 

 p. 537), an account was given of a study of varietal characters and the isolation 

 of pure forms of tobacco. In the present contribution additional data are pre- 

 sented relating to the behavior of different strains in later generations. 



In the progress of the investigation it was found that parthenogenesis in 

 N. tabacum, under the conditions of the experiment, is negligible. In all 

 characters except height, the Fi generation is intermediate between the parents. 

 The limits of variation in the Fj generation have been as great as those of both 

 parents combined or have exceeded these in both directions. Selected variates 

 of the Fs generation ga^e cultures which differed in their range of variation 

 from one another, and often from both parents. It was found that while the 

 height of tobacco plants may differ only slightly, the factors on which such 

 height depends may be almost entirely different. The number of leaves per 

 plant was not found to depend on the height of the plant, and was also inde- 

 pendent of the environment. A distinct segregation was observed as regards 

 the arrangement of the leaves on the stem. The author states that the most 

 suitable leaves for measurements arv. those occurring in the center of the plant, 

 and that venation of the leaves is one of the most constant characters of the 

 plant, parental forms having been reisolated in the third and fourth generations. 



In conclusion the author summarizes the data, stating that " a study of the 

 characters of N. tadacum shows that there is no inherent difference in the 

 mode of inheritance of ordinary qualitative characters (such as the color of 

 the corolla) and of those characters connected with the size of the organs which 

 are subject to fluctuating variability. All the results obtained can be explained 

 by the Mendelian assumption of segregation of characters, combined with the 

 hypothesis that in connection with each character a large number of factors 

 exist, each of which can be inherited independently." 



The flowering of Geranium robertianum under the influence of various 

 physical conditions, R. Stager {Bot. Centhl., Beihefte, 30 {1918), 1. Abf., No. 1, 

 pp. 1-16; abs. in Rev. Set. [Paris], 51 {1913), II, No. 8, p. 245).— The flowering 

 of this plant has attracted much attention on account of the apparent variation 

 in its adaptation for pollination. The author claims that two types of flowers 

 are produced, depending upon the climatic conditions at the time, protandrous 

 flowers if the weather is fine and the temperature fairly high, and protogynous 

 flowers in cooler and more humid surroundings. From 1 to 3 days are required 

 for the pollination of the flowers. A high temperature and dry air favor pre- 

 cocious pollination, while low temperature and moist conditions retard it and 

 favor the greater growth of the styles, resulting in a protogynous condition. 



The relation between tuberization and infestation of the roots of Spi- 

 ranthes autumnalis by endophytic fung-i, C. Beau {Conipt. Rend. Acad. Sci. 

 [Paris], 157 (1913). No. 13, pp. 512-515). — A study was made of S. autumnalis 

 in the light of the investigations of Bernard (E. S. R., 14, p. 635; 18, p. 1031). 

 The author found that while this orchid, which produces new tuberous organs 

 each year, requires the presence of endophytic fungi to begin the development 

 of its tubers, in a mature state it is independent of the symbiotic relationship. 



Influence of radioactivity on vegetation, M. Vacher {Bui. Soc. Nat. Agr. 

 France, 73 {1913), No. 5, pp. 557-372).— Discussing the results obtained from 

 experimental work done by Petit and Ancelin (E. S. R., 29, p. 32G), Stoklasa 

 (E. S. R., 28, p. 731), and others, the authors state that radioactivity appears 



