636 EXPERIMENT STATION EECOED. 



injury does not always become apparent at first, in some cases not within 2 

 years; and that sunlight favors the injurious action of the tar products in 

 certain cases. 



A bibliography is appended. 



A study on the influence of starvation of the ascendants upon the char- 

 acteristics of the descendants, I, J. A. Haeris (Amer. Nat., Jf6 {1912), No. 

 5Jt6, pp. 313-3 'fS, dgms. 7). — The author presents his first report on a study of 5 

 series of garden beans, giving a statement of the problem and a description of 

 the methods, the work having been carried on for some time and involving 

 about 21,000 individuals. 



The purpose of the investigation was to ascertain whether the artificial de- 

 pauperization of the ancestors has any influence upon the characters of the 

 offspring. Beans were planted in ordinary fertile and sterile soils or good and 

 poor agricultural land, and the influence of from one to three generations was 

 studied. Thus far, it is stated, hardly any difference can be detected by the 

 eye in the field, but the statistical constants seem to show a slight influence of 

 the treatment of the ancestors in the form of a slight decrease in the number 

 of pods per plant. 



The data are as yet insuflScient to justify any discussion of the question of 

 the cumulative influence of the starvation conditions or of the mechanism 

 through which the characters of the plants are modified. 



Chromosome numbers in Triticum and -ffigilops, W. Bally (Ber. Deut. 

 Bot. Gesell., 30 {1912), No. J,, pp. 163-172, pi. i).— This is a cytological contri- 

 bution to the study of relation among the wheats, based upon a study of the 

 chromosome numbers. It is stated that (1) Triticum, dicoccoides has 8 simple 

 chromosomes, in this respect resembling T. ■vulgare and Secale cereale, and (2) 

 ^gilops ovata, which is able to hybridize with species of Triticum, has 16 simple 

 chromosomes. 



A bibliography is appended. 



Soil moisture in the cottonwood dune association of Lake Michigan, G. D. 

 Fuller {Bot. Gaz., 53 {1912), No. 6, pp. 512-514, /iff. i).— The author records 

 data regarding the range of soil moisture in the' cottonwood dune association 

 upon the shores of Lal^e Michigan. This area is considered an open association 

 of a single tree species, together with a scanty undergrowth of shrubs and 

 grasses, developing upon more or less rapidly moving dunes, possessing a high 

 rate of evaporation and exhibiting many strongly xerophytic characters. The 

 almost complete absence of herbaceous undergrowth and the expanse of bare 

 sand give it a desert-lilie aspect, but below the superficial layer of sand an 

 abundant and unfailing water supply has been found. 



The wilting coefficient of the dune soil was determined, by the method of 

 Briggs and Shautz (E. S. R., 26, p. .628) to be 0.75 per cent. Throughout the 

 most arid portion of the season the surplus of growth water was found to 

 average 2.2 per cent, showing that, considered upon the basis of its soil moisture, 

 the association is decidedly mesophytie. The causes of the xerophytic character 

 of the vegetation are believed to be the high evaporating power of the air and 

 the instability of the substratum. 



From the data obtained the author believes that the determination of soil 

 moisture, related to plant growth through the wilting coefficients of the soil, 

 will afford an efficient means of making quantitative studies of the water sup- 

 plies of the subterranean parts of plant associations, and enable students of 

 ecology to analyze more closely the effects of various factors influencing the 

 production of any particular plant association. 



A comparison of the rates of evaporation in certain associations in central 

 Illinois, H. A. Gleason and F. C. Gates {Bot. Gaz., 53 {1912), No. 6, pp. .',78- 



