AGEICTJLTTJEAL BOTANY. 421 



bases. Rapidity of gi'owth is said not to be proportional to the turgor of the 

 plantlets employed. He inclines to the view that differences in rate of growth 

 are to be ascribed to differences in degree of hydration of the plasma colloids. 



The influence of different substances on the germination of seeds and on 

 plant growth, I, II, III, T. Bokorny {Biochem. Ztschr., 50 {1913), No. 1-2, 

 pp. 1-118). — Continuing worli previously noted (E. S. R., 28, p. 527), the 

 author gives the detailed results thus far obtained from an extensive but still 

 incomplete investigation on the influence of salts, etc., on seeds and seedlings 

 of several plants. The general conclusion is reached that for most substances 

 regarded as poisonous, concentrations exist which promote plant development ; 

 but that since the points of injurious concentration on the one hand and of In- 

 operative dilution on the other are generally close together, the limits within 

 which stimulation occurs are probably too narrow to be of practical importance 

 in most cases. 



Frost and lig'ht as factors in seed germination, W. Kinzel (Frost und 

 Licht als beeinflu-ssende Erdfte hei der Samenkeimung. Stuttgart, 1913, pp. 

 YII+110, pi. 1, figs. 4; abs. in Ztschr. Bot., 5 (1913), No. 5, pp. 377-3S0 ) .—Be- 

 sides a review of related literature, the author gives numerous detailed and 

 tabulated data obtained from his investigations during about 10 years on the 

 effects of light, frost, and other influences on the germination of seeds from 

 widely divergent groups, largely wild plants or weeds requiring control. 



The influence of the endosperm on the development of the embryo, M. 

 DuBAED and J. A. Urbain (Compt. Rend. Acad. Sci. [Paris], 156 (1913), No. llf, 

 pp. 1086-10S9). — As a result of their repetition of certain experiments made on 

 wheat, oats, barley, etc., the authors state that the endosperm of seeds, while not 

 indispensable to early embryonic development, is helpful thereto, especially dur- 

 ing the first stages. In general the reserves enclosed with the embryo are indis- 

 pensable, as shown by the fact that if decreased to a certain point in certain 

 cases the plantlet dies, having reached only a very limited development. 



The formation of the anthocyan pigments of plants. — IV, The chromogens, 



F. Keeble, E. F. Aemsteong, and W. N. Jones (Proc. Roy. Soc. [London], Ser. 

 B, S6 (1913), No. B 588, pp. .308-317).— This is a contribution to the biochem- 

 istry and genetics of flower pigmentation and deals primarily with the chromo- 

 gens occurring in flowers. 



The formation of the anthocyan pigments of plants. — V, The chromogens 

 of white flowers, W. N. Jones (Proc. Roy. Soc. [London], Ser. B, 86 (1913), 

 No. B 588, pp. 318-323). — This communication is in continuation of a series on 

 the formation of pigments in plants and describes principally the chromogens of 

 white flowers. The method pursued in this investigation was that of bringing 

 chromogen and oxidase together, causing them to interact with one another. 

 By such methods the author has separated white flowers into the following 

 types : Those which contain an oxidase and a chromogen, those which contain a 

 peroxidase and a chromogen, those which contain a peroxidase but no chromogen, 

 and those which contain no oxidase or peroxidase. 



Studies of irritability in plants. — III, The formative influence of light, 



G. J. Peirce (Leland Stanford Jr. Univ. Pubs., Vndv. Ser., Dudley Mem. Vol., 

 1913, pp. 62-80, pi. 1). — By means of a multiple clinostat, a description of which 

 is given, the author carried on experiments on the prothalli of ferns and plants 

 of liverwort, Fimbriaria calif ornica, Antlioceros fusiformis, white mustard, and 

 wheat to determine the effect of light on their development. 



Analyzing the results obtained, he shows that light affects the direction, kind, 

 rate, and amount of growth. It was found that a uniform illumination in- 

 creases symmetry in development. In certain instances this symmetry appeared 

 to be complete, a dorsi-ventral structure giving place to a radial one. The 



